Great strides have been made since MiniVend's early days. The great majority of ISPs provide some CGI service, and more and more run systems that are compatible with MiniVend. The new catalog configurator for MiniVend makes setup much easier.
A word of warning -- if you chose your ISP mostly on price, you can expect problems. There is no such thing as a free lunch; the low-cost providers typically have heavily-loaded machines and many domains. The more domains and the more load the unhappier you will be with MiniVend. MiniVend works best on a fast machine with plenty of memory.
A few Internet Service Provider (ISP) systems still have difficulty with one or the other aspect of running MiniVend. A few cannot (or will not) run MiniVend at all. On top of that, many times ISP personnel are too busy to help, won't help, or don't know enough to help. Some are secretive about details of the setup of their systems.
All in all, you can have a fair amount of confidence that your ISP can run MiniVend. Or, you can get one who will. 8-)