or planning to have kids. If you have to ask, you can't afford it. Seriously, your question is a good one. Make yourself a materials list. For example, three sheets of plywood, 4 or 5 2 by 4's 8 feet long, 8 or 10 2 by 2's 8 feet long, a 4 foot shop light fixture, a fixture for heat source, UV light bulbs, timers, rheostats, wire.
You get the picture. If you start with a baby in a 40 gallon breeder tank you will need to move your tegu up to a big enclosure with the items listed above by the time it is a year old. Bert Langerwerf, Agama International reccomends 32 sq. ft. of floor space for an adult. That's a 4 by 8 sheet of plywood on the floor. Hope this helps. Happy building.
Mike B