PracticePaySolutions.com  Relatively low setup ($125) and low monthly fees allow manual card processing for as little as $22 per month, and automatic processing for $27 (plus the industry standard per transaction percentages of around 2.15%).

2checkout.com  This company is unique because after the $49 setup fee, there are no monthly fees.  Instead, they take a higher per transaction fee of 5.5%.

ProPay.com  Here’s another option for low-volume sellers.  They have a yearly recurring fee of $35 (compared to free at 2checkout), but they only charge 3.5% per transaction (compared to 5.5%).  They do have a transaction limit of $250, so this doesn’t work if you’re selling items that cost more than that.