What does it typically cost to integrate 2Checkout into a website?

I think the price is a tad bit too much. Usually the integration is quite easy. As pointed out earlier in other answers, 2CO supports multiple shopping carts, so usually integration is a breeze. Unless your development is 100% bespoke, this should be an easy fix. Might be 1-2 hours worth of worth, so US$ 750, is high.