I use the Etch Mate. Can't say it's the most affordable, but I like it. I will say, no matter what method you use, it's a lot easier if you anneal the metal first. You hold it over a flame just long enough to change the color a bit, and this softens the metal. After that it's easier to bend. Some PE sets out there are so stiff it's hard to get a sharp corner otherwise. Just don't do this with pre-painted PE.