1. Understand what you’re buying.

When you get right down to it, credit card processing doesn’t vary much from one merchant service to another. There might be some bells and whistles, but before you pay more for them, make sure they’re something you really need. On the flip side, a dirt-cheap service may offer virtually no “service” at all when push comes to shove.

2. Read the fine print.

There are well over 120 interchange categories—the classifications that determine the cost to process a credit card transaction. These fees go to the card network (Visa, MasterCard, and the rest) and to the issuing bank. The processor—your merchant service—makes its money on an add-on fee. Usually you’re just presented with a “discount rate” that lumps these two together. Moreover, processors like to condense those ten-dozen-plus categories into about three tiers based on the category average. That means you can easily end up paying more than you should.

3. Negotiate, negotiate, negotiate.

Once you’ve read the fine print and know what you’re being charged, it’s time to negotiate exactly what your credit card processing costs will be. Your current merchant processor (or the one whose sales rep is sitting in front of your desk trying to get your business) isn’t the only game in town. Shop around. Choose the best rate, or use a better rate as a negotiating point with your current processor.

4. Watch out for minimums.

Some contracts specify either a minimum fee or additional fees if you fail to process a certain volume each month. Particularly if you are setting up a new business, be wary of these minimum fees.

5. Breaking up shouldn’t be hard to do.

Some merchant service contracts include a cancellation fee. While it’s certainly not a hard-and-fast rule, you have to wonder why a merchant service would charge you money for leaving them. Do they have trouble keeping customers?