I have a store on Etsy for my art, started this last January, same time as DPW. Etsy charges a small fee on every sale, that's true, but it also has a built in traffic, community of people who are already there to shop. If you do your tags right people may find your work any time (not only on the day it's listed - in fact, that does not matter any longer on Etsy). I have to say that I had more sales from Etsy store by now than on DPW, and I could see that most of them did not come from DPW, but from Etsy search. So I look at that small fee that Etsy charges as a tiny advertising expense. PayPal on the other hand, as far as I know, just gives people a way to pay, it does not bring traffic on its own. I love being here on DPW, but having my work only in my DPW gallery does not give it enough chances to be seen, so I also list it on Etsy, and on my website of course. I really believe it's best to give your work as much exposure as you can afford. That's just my experience.