I did some research and wrote about this issue in the latest issue of Aquaponics Survival Communities. I showed charts, prices, and growth rates.

You'll get your best bang-for-your-buck if you buy 7-8" Trout in the fall, and 7-8" Tilapia in the spring. At those sizes, you can grow them to plate size in 6 months.

For insulation, I'd encourage you to check this out. Cheaper and better insulated than anything else you're likely to find.