While there are dozens of companies that offer credit card processing solutions for small businesses, we like these four – PayPal, Square, Shopify and SparkPay – because they don’t use complex pricing structures that require business owners to understand the complexities of interchange fees or discount rates.

For small businesses that have more important things to focus on, a flat-fee structure for credit card processing is an ideal solution. Our top picks are also transparent about their pricing online: Unlike some of their competitors, they don’t require you to contact a salesperson to find out how much your business will pay to accept credit cards.

Inexpensive Credit Card Processing for Small Businesses

The processors below will all do business with companies whose monthly or annual sales are next to nothing. You can sign up with them when you’re just starting out and stick with them as you grow, though at some level of sales volume you might find that another provider will save you money.

1. PayPal

PayPal enables businesses to accept all major credit cards through a website or mobile device, as well as in person.

– Businesses do not pay any startup fees, monthly fees or termination fees.

– For U.S. online transactions, the fee is 2.9% of each transaction, plus 30 cents.

– For point-of-sale transactions using a mobile card reader attached to your smartphone or tablet, PayPal charges 2.7% per swiped transaction and 3.5%, plus 15 cents per keyed or scanned transaction.

– Your first mobile card reader is free; additional readers cost $14.95 each.

– PayPal’s fee for chargebacks is $20.

– PayPal does not have the option to create an online store, but you can add PayPal to your existing online store.

Bonus: Businesses that use their PayPal earnings to make purchases using a PayPal debit card earn 1% cash back on every purchase.

2. Square

Square allows companies to accept all major credit cards through the Square register app for point-of-sale transactions, through an existing online store or a free online store hosted by Square, or through a magstripe reader attached to a smartphone or tablet.

– There are no sign-up fees, monthly fees or early termination fees.

– For all swiped, dipped or tapped transactions, Square charges 2.75%.

– For keyed-in transactions, Square charges 3.5%, plus 15 cents per transaction.

– Square’s magstripe reader for smartphones and tablets is free.

– Square covers all chargebacks up to $250, with a limit of $250 per month.

– Square lets merchants set up a free online store with no monthly fees or hosting fees.

Bonus: Square’s online stores are free.

3. Shopify

Shopify lets businesses accept all major credit cards through an existing ecommerce site or by building one with Shopify. The service is similar to Square, but its higher cost may be justifiable for merchants who do a high volume of online sales and want to use Shopify to create and manage their online store.

– Shopify offers several plans, and each has a monthly fee. You’ll want to do the math with your monthly credit card revenues to see which plan is the most cost effective for your business and whether the additional features that come with the different pricing tiers will be valuable to you.

– Rates for in-person transactions are as low as 2.4% per transaction, with a $299 monthly fee.This payment plan, called Advanced Shopify, also charges 2.4% plus 30 cents per transaction for online payments.

– The midrange plan, simply called Shopify, has a $79 monthly fee. In-person transactions cost 2.5%; online payments cost 2.6%, plus 30 cents per transaction.

– The entry-level plan, called Basic Shopify, has a $29 monthly fee. The in-person rate is 2.7%, and the online rate is 2.9%, plus 30 cents per transaction.

– The most basic plan of all, Shopify Lite, costs $9 per month and doesn’t come with an online store. But it does let you accept payments in person or through your existing website at the same rates as Basic Shopify.

– A swipe card reader that plugs into your smartphone or tablet is free.

– Shopify’s chargeback fee is $15.

Bonus: Shopify offers a 14-day free trial.

4. Spark Pay by Capital One

Spark Pay by Capital One has a more complex pricing structure than PayPal or Square, but a simpler one than Shopify. There are two pricing plans for credit card processing.

– With the Go Plan, you pay only for the transactions you run each month at a rate of 2.65%, plus 5 cents for each swiped MasterCard, Visa or Discover transaction; and 3.70%, plus 5 cents for each swiped American Express transaction and for keyed-in transactions from any credit card company. There is no monthly fee.

– To pay less per transaction, you can opt for the Pro Plan, which has a $19.99 monthly fee. Processing rates drop to 1.99%, plus 5 cents per transaction for swiped MasterCard, Visa or Discover purchases; and 2.80%, plus 5 cents for each swiped American Express transaction and for keyed-in transactions from any credit card company. Capital One says this plan makes sense for businesses that process more than $3,000 per month

– The first card reader is free; additional readers cost $13 each.

– Like Shopify, Spark Pay offers online stores. The entry-level steel plan costs $24.95 a month, lets you list up to 100 products and allows for up to 2 GB of traffic and 250 MB of storage. The bronze, silver, gold and platinum plans cost progressively more and allow for more product listings, traffic and storage. The drawback is that Spark Pay does not appear to integrate with existing online stores.

– The chargeback fee is $15.

Bonus: The site has a simple click-and-drag tool to help you see what your estimated swipe fees will be given your monthly credit card volume (though it’s a bit cumbersome to use for volumes under a few thousand dollars). As with Shopify, you can try the online store feature free for 14 days. And you’ll get a $50 bonus if you process $5,000 in transactions in your first three billing cycles.

The Bottom Line

The best credit card processor for your small business depends on what’s most important to you, whether that’s help with creating an ecommerce website or simplicity in pricing. PayPal, Square, Shopify and Spark Pay are all solid options. If none or them seems right to you, though, there are many others.

Want to learn how to invest?

Get a free 10 week email series that will teach you how to start investing.

Delivered twice a week, straight to your inbox.