These cash advance products are structured on a factoring basis instead of traditional loan + interest rate. Most are structured like this
Merchant needs $10,000
They agree to pay back $12,500 by having the processing company deduct 20% of their daily credit card receipts until the money is paid back. They usually structure it so that they are paid back within 6-8 months but there is no time frame.
If you have good cash flow and just need the money for new equipment or for a one time payment it might work for you. If you are doing it because you are constantly falling behind on your bills or cash flow is really tight, these can be crippling. Giving up 20% of your daily sales can be tough on a small business.
Pros- No time frame, Doesn't affect Credit, You pay back on your schedule so if you have a busy day more is paid back, if you do no business one day there is no payment
Cons- Expensive money (25%-40%), You pay back 20% of your daily credit card sales, often end up in a perpetual borrowing cycle.
Hope this helps.