There are several types of companies you can turn to for MasterCard and Visa merchant services.

Banks

Your existing business bank should be the first place you turn. Banks can be the easiest source to turn to for credit card services; many offer service packages for businesses that include MasterCard and Visa merchant services. It can be tough to get approved from this channel, though. Banks are likely to scrutinize your business more closely before deciding whether or not to accept your application.

Third Party Processor

Third party processors dedicate themselves to handling credit card processing. As such, they take care of different aspects of the transaction process such as authorization, billing, reporting, and settlement.

Independent Sales Organization

An independent sales organization (ISO) is essentially a registered credit card merchant broker who represents one or more third party processors. They set up and service credit card merchants, but do not do the actual processing. ISOs are less selective than banks, but that comes at a somewhat higher price. They are also not strictly regulated the way banks are, so be particularly vigilant when evaluating potential suppliers.

Association

Small business and trade associations often offer MasterCard and Visa merchant processing at discount prices. They are a particularly good resource if companies in your industry historically have trouble attaining credit card merchant status.