I need help with choosing soil for my venus fly trap.?

You're on the right track with the peat moss. Venus fly traps are native to the southeast where we have acid soil. You can use either straight peat moss. I've purchased it in small bags at Lowe's and Walmart. Or you can mix 1/2 peat moss and 1/2 perlite. The perlite is also available in a small bag. For more information, check out the website I mentioned as a source of information.