I generally try to create my own molds- there are some really cost effective, easy-to-use products, but you must make sure that you choose your products with care.
If they arrive on time, Townsend Atelier's Knead a Mold and Brush a mold, which work in conjunction with their Swell Shell, are easy to use. Beware, though. Townsend Atelier has great customer service until something goes wrong. Townsed Atelier's customer service folks take your money, make promises, and then you may have to wait months for your product to arrive.
I recommend trying to make your own molds, but stay away from Townsend Atelier.