I picked up my first mids at various thrift shops or a used sports store in town. I don't think I paid much more than $10 for any of them. A POG 4 stripe, a few St Vincent Pro Staff 85s, a couple Kramer Staffs, a Mag Pro 90, PK Copper Ace 90, Wilson N90 (I think it was $15), a couple others that are somewhere in my overflowing closet... The more I find and play with the more I realize that I could play fine with just about any of them as long as I experimented a bit with strings.
You have been asking about the Diablo for months. Demo it. It's cheap. Pick up a couple TW Holiday gift cards for 20% off and you can get two Diablos for $160.
Tour 100T ESP - Pro Line X 16