$4000 isn't exactly a lot of money for a serious investor in a new business. And besides, you can usually get them cheaper if you buy them in bulk.

Vending machines are not exactly top of the line technology, and if you accept bitcoin you won't even need any kind of money accepting and storing mechanisms. So they'd actually be cheaper.

It also depends on if you need your vending machine to also keep your products cool or not. Obviously a vending machine that sells candy would be much cheaper, since candy in general doesn't need to be cooled.

Some machines can go for as little as a couple of $100s