So far Kevin i`ve been lucky with food costs. He came with a bag full of pre frozen small turkey balls, had old beef in the freezer. But i would imagine it would be more then the average ball python cost/feed ratio. You`ll never throw anything away in the meat dept even if it`s freezer burnt it`ll be alrite for the Tegu. Fruits and veggies shouldn`t cost that much in season. You`ll spend a bit to figure out what he/she likes but then it shouldnt be that bad.
In some areas you can even talk with local food places, some may give or sell for cheap stuff they plan to throw out. Also be a good idea to invest in a small meat grinder for makin turkey balls and such. Just make sure anything you feed is raw and unseasoned.

And yes roaches are part of thier diet if the`ll eat them. If they`ll eat it .... feed it to them.

Cheers,

John