#1 Silica Sand is my answer for everything. I have done several whole trucks with it. At $5 for an 80 pound bag, you cant go wrong. This is NOT play sand. Play sand is way bigger and would destroy anything you are pointing it at. The stuff I am talking about is the consistency of fine sugar/almost flour. It wont warp your work at 110psi. If you are doing carbs or highly rusted zinc or cad plated parts, turn the pressure down to about 40psi. Other than that, I use it for everything. It gives you deadly Silicosis if you don't wear a good respirator, so just like when painting or doing anything else with airborne particulates, be safe. Once you try this stuff you will wonder why anyone would purchase all the rest of the media stuff they sell. You get it at the local lumber yard. The brand I buy is Quickcrete. Downside is speed. If you have really tough substrates, it will take longer. Since I have way more time than money, this isn't a factor for me, however if you want things done faster, go with something else.
If you are outside doing a frame and want to save money, get two 4x8 sheets of plywood and make a backstop (corner) and focus your blasting in that direction. Put a tarp on the ground, use a sifting screen, and re-use as much of the sand as you can trap.
