Does anyone use disposable piping bags.  If so what is the best one to use - Wilton??  Kopycake???  Other???

AWilton is likely your most readily available and affordable, I think. I used bags from the bakery supply when I worked at a bakery and honestly couldn't tell you that they were any better than Wilton's bags. They are disposable bags, after all,

Kee-seal

I use decopac. Works great! I've never had a tear or burst. :)

KopyKake for sure. The bags are a little softer so I find them easier to work with, and they don't have the seams like the rolls of bags do.
 

I just bought cheap ones on Ebay from China and they work just as well as the free KopyKake ones I got with my projector.
 

Thanks to all who replied.  I think I will try all that were suggested.  I am just a hobbiest now but looking for a way not to have so much cleaning up to do.  Hate washing bags.  Thanks again.  You are all just great.  Vicky