Go to your local track and see what everyone is running, Then see what you want to run, 2wd buggy, 4wd buggy, 1/8 buggy, truggy, slash, you get the idea. Then decide if you want electric or gas, then see what your local hobby shop has parts for. finally see how much money you want to spend

. Stock class is usually the least expensive and fun class bc money is not a big factor, it comes down to skill.
Good luck, Matt