Most business owners choose their payment processor the same way they’d go about picking a car mechanic. Unless you’re very familiar with the matter, you just have to trust the expert won’t rip you off. Unfortunately, many payment processors will try to take advantage of your goodwill. Here are five payment processor scams that you need to watch out for.

1. Misleading Rates

Processors who use a tiered pricing model for their fees will often advertise a low rate without clarifying that it only applies for “qualified” charges. If you’re making your purchases through a business credit card, you’ll have to deal with higher processing rates, which aren’t advertised at all. Some processors also charge a low rate to begin with but raise it over time.

The best way to avoid getting reeled in by misleading rates is to stay away from processors who use tiered pricing altogether. Instead, go for a processor that charges a flat rate or uses membership and interchange-plus pricing.

2. Shady Salespeople

Sometimes, a salesperson from the processing company will stop at nothing to get you to sign up. They’ll tell you everything you want to hear, even if it’s something they can’t promise. Once you’re locked in a contract, they’ll suddenly disappear. However, they’ll still make a residual percentage of every dollar you process.

Choosing a payment processing company with strong values will weed out most untrustworthy salespeople. Before choosing your vendor, ask for references from their other customers and factor in those opinions as well.

3. Equipment Leasing

As a general rule, credit card terminal leasing isn’t a good idea. If a provider is pushing you to do it, they likely don’t have your best interests at heart. Leasing a payment terminal will set you $30 to $100 over two to four years, which can add up to thousands of dollars. Since you can buy a new terminal for a few hundred dollars, leasing is never worth it.

Don’t have the funds to buy the equipment upfront? Go for a short term rental until you can afford it. Alternatively, you may be able to reprogram your current equipment, which a lot of providers offer to do for free.

4. Exclusive POS Software

Some payment processors will try to sell you a POS system that can supposedly do everything you need to run a business. This may technically be true, but these systems tend to be tied to a single processing service. This allows the processor to strong-arm you into paying a higher rate, as you’re unlikely to give up the system’s features to save money.

This is why you should always be wary of POS systems that only work with some payment processors. If a processor offers you a specific POS system, ask whether it works with other processors first.

5. Hidden Fees

Chances are, you’ve had a conversation with a processor who told you that your rate is 1.3%, “no matter what.” What they don’t tell you is that they also have surcharges, which brings your effective rate closer to 3%. Even Worldplay, the biggest payment processor in the United States, tackled added fees on certain transactions without explaining them properly.

The solution is simple enough: never sign on the dotted line without reading the fine print. Watch out for verbiage that allows the processor to charge additional fees. It’s a tedious task, but it can save you hundreds of dollars per month.