<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by MoreMiles:
In addition to the 2-3% credit card fee, there is also the fraud risk.
Consider this situation: the store owner gives you the cash so he can put someone's sale on your credit card. You take the cash, and file a charge-back 3 weeks later. The merchant is now out of money. You can claim that you never got the merchandise etc.
No store owner, no matter how friendly s/he is, will want to take this kind of risk.</font>
There's always a fraud risk. One doesn't do this sort of operation with strangers. If my brother owns the store, for example, there's little chance of me stiffing him. Doing that charge back thing is probably fraud in the broad criminal sense, as opposed to screwing the merchant.
I don't have anyone lined up at the moment, but there are possibilities...