E-Commerce projects are nowadays run with funding from merchant accounts. It is almost impossisble to succeed and carry on fund management without having good merchant account facilities.
Free Credit card processing is one such thing if you are not doing it on a very large scale. If you are a small biz then you can take adavantage of this facilities that your bank provides you with.
On another note if your payments are large then free services is not the way to go . Go for good trusted providers who have a small monthly fee which is negligible when compared to your turnover.