One that comes to mind is PC-Charge. You can do a few test transactions, but can't really ""settle"" for the day. This bit me in a big way several years ago, when client processed orders all day, but couldn't settle the batch (which included previously processed pre-auth's as well as new ones). This spirals out of control quickly when clients cash flow is interrupted and the transactions must be settled within 72 hours (give or take). No matter what, these issues will find their way back to the partner. When I hire a GC to build an addition, I'm not going after the plumber because my faucet leaks.