I'm looking to see what type of mantis are available right now. Tried lookin on chameleon food link, but no luck. I know I heard someone on here sales them.
I raise them. Try the mantid forum. They are expensive feeders if you are not raising them yourself. Depending on species and age, you're probably looking at a couple bucks to $100 each.
Just going by your avatar. 8 month old panther will take down just about any medium to large mantis. I raise Madagascan marble mantis for feeding my larger panther / parsons.
I suggest getting an ootheca and some fruit flies. Many members sell them. I often get mine from pssh and my Chameleons LOVE them. Sometimes I keep some and raise them to adults. They make interesting pets too.