Stax (Fattmerchant) vs. Payment Depot: Is a Membership Model Worth It?

Stax (formerly Fattmerchant) and Payment Depot both promise to cut your processing costs by charging a flat monthly membership fee instead of a percentage markup on every transaction. For businesses with high monthly volume, that model can genuinely save money. For many small and mid-size businesses, though, the subscription fee eats up the savings — or worse, you end up locked into a platform that doesn't fit how you actually run your business. Here's a clear-eyed comparison of both models, and a framework for figuring out which approach is actually cheapest for you.

How Subscription (Membership) Pricing Works

Both Stax and Payment Depot operate on the same basic idea: you pay a fixed monthly fee, and in exchange your per-transaction costs drop to interchange (the wholesale rate set by Visa and Mastercard) plus a very small fixed markup — often a few cents per transaction rather than a percentage. The logic is straightforward: the higher your monthly card volume, the more that percentage savings compounds, and the more the membership fee pays for itself.

Neither company publishes a single universal rate — plan tiers, monthly fees, and per-transaction costs vary by volume and business type, so always verify current terms directly with each provider before you make a decision. That said, the structural approach is consistent: swap a percentage markup for a membership fee.

Stax at a Glance

• Model: Monthly subscription; interchange passthrough plus small per-transaction fee.
• Software platform: Stax offers its own integrated suite — invoicing, recurring billing, analytics, a virtual terminal, and ecommerce tools — all tied to your Stax account.
• Hardware: Stax provides compatible terminals and mobile readers; your options are generally limited to what they support.
• Who owns the merchant account: You get your own merchant account, which is a genuine plus — you're not lumped into an aggregator like you would be with Square or Stripe.
• Contract / lock-in: Verify current contract terms directly; early-termination policies can vary by plan and time of signup.
• Best volume range: Stax generally markets to businesses processing several thousand dollars a month or more; below a certain threshold the monthly fee is hard to justify.

Payment Depot at a Glance

• Model: Monthly membership; interchange passthrough plus a small per-transaction fee (similar structure to Stax).
• Software platform: Payment Depot is more narrowly focused on processing; it integrates with third-party POS systems and gateways rather than offering a deep proprietary suite.
• Hardware: Compatible with a range of terminals; integrates with popular gateways like NMI and Authorize.Net.
• Who owns the merchant account: You get your own MID — again, a real advantage over aggregators.
• Contract / lock-in: As with any provider, confirm current terms directly. Payment Depot has historically emphasized no long-term contracts, but always read what you sign.
• Best volume range: Similar to Stax — the membership fee makes economic sense at meaningful monthly volume. Very low-volume businesses often come out behind.

Head-to-Head: Where They Differ

• Software depth: Stax leans into an all-in-one platform with invoicing, subscriptions, and analytics built in. Payment Depot leans on integrations with tools you may already use. Neither is objectively better — it depends on whether you want one ecosystem or flexibility to mix and match.
• POS hardware flexibility: Payment Depot tends to work with a broader range of existing terminals. If you already own a Clover, PAX, Valor, or Dejavoo terminal, it's worth asking both providers whether they can support it — because replacing working hardware is a real cost that the membership fee math often ignores.
• Ecommerce and online tools: Stax has more built-in ecommerce infrastructure. Payment Depot relies more heavily on gateway integrations.
• Support model: Both offer customer support, but neither is a local agent who knows your business. If you'd rather talk to a human who can walk your statement line by line, that's a real gap with both.

The Math Problem with Membership Pricing

The subscription model only wins when your monthly volume is high enough to offset the membership fee. Here's a simple mental model:

1. Find out what you're currently paying as a percentage markup above interchange (your statement or a free analysis can show you this).
2. Multiply that markup percentage by your average monthly card volume. That's your current markup cost per month.
3. Compare that number to the membership fee. If the membership fee is lower, you save. If it's higher, you don't — regardless of how low the per-transaction rate sounds.

Many businesses with seasonal volume swings, low average transaction sizes, or overall modest monthly volume find that a well-structured interchange-plus plan — with no monthly membership fee — outperforms both Stax and Payment Depot on total cost. The math is the math.

What Both Models Don't Always Advertise

• Interchange still varies. Both platforms pass interchange through, and interchange isn't flat — it shifts based on card type (rewards cards, corporate cards, etc.) and how the transaction is processed. Your actual cost per transaction will fluctuate regardless of the membership structure.
• Gateway and software fees add up. Depending on your plan, fees for gateways, virtual terminals, or advanced features may be on top of the membership fee. Read the full fee schedule, not just the headline number.
• You may still face hardware costs. If either provider can't support your existing terminal, you're buying new equipment — that's a real upfront cost that rarely appears in the comparison math.

Who Each Model Is Best For

Stax may be a good fit if you process a relatively high monthly volume, want an integrated software platform for invoicing and recurring billing, and are comfortable working within Stax's ecosystem for hardware and software.

Payment Depot may be a good fit if you process significant monthly volume, prefer flexibility in your gateway and POS integrations, and want to keep more of your existing tech stack.

Neither may be your best option if your monthly card volume is modest, you process lots of small-ticket transactions, you want to keep your existing POS hardware without restrictions, or you'd benefit from cash discount / dual pricing programs that reduce your processing cost to near zero.

A Third Path Worth Considering

Membership pricing gets a lot of attention, but it's one model among several. A well-structured interchange-plus plan with no monthly membership fee, combined with a cash discount or dual-pricing program (where compliant and disclosed properly), can outperform both Stax and Payment Depot for a wide range of businesses — especially those with lower volume, mixed card types, or a strong cash customer base. You also get to keep hardware you already own, work with a local agent who reads your statement with you, and maintain full ownership of your merchant account and your book of business with no lock-in.

Frequently Asked Questions

Is Stax or Payment Depot better for a small business doing under $10,000 a month in card sales?

At lower volume levels, the monthly membership fee for either platform is often difficult to recoup through the per-transaction savings alone. Many small businesses in that range are better served by an interchange-plus plan with no subscription fee, or by a compliant cash discount program that shifts the cost of card acceptance away from the business entirely. Run the actual math for your volume before committing to any membership model.

Can I keep my existing POS terminal if I switch to Stax or Payment Depot?

It depends on the specific terminal and plan. Both providers have compatible hardware lists, and not every existing terminal is supported — which means you may face hardware replacement costs that don't show up in the advertised fee comparison. Before switching, confirm in writing whether your current terminal (Clover, PAX, Valor, Dejavoo, or otherwise) will work, and factor in any hardware costs when you do the math.

How do I know if I'm actually overpaying my current processor?

The fastest way is a free statement analysis from a payment specialist who can calculate your true effective rate — total fees divided by total volume — and identify exactly where markups, junk fees, or misclassified transactions are costing you. That gives you a real baseline to compare against any alternative, including membership models. Request a free statement review from a local specialist and get a clear savings breakdown before you make any switch.