It seems like such a silly thing to even ask the question. I generally prefer to just do things rather than talking about an idea until I'm bored with it before it's even occurred. It would take 20 minutes to setup a PayPal account and stick a donate button somewhere on the site. If people have been asking for a way to donate cash to the project, when they see the donate option they're going to fork over some cash. Even if you only get a couple of people donating a few dollars, if nothing else that would compensate you for the time it took to setup the donation form. If on the other hand, a lot of people donate even a little bit of money, it would go to greatly offsetting some of the costs of managing the project.
I would suggest adding a "Donate to PixelPost" button inside the admin panel of the next release of PP. That way even the people who use it the most will get the idea in their head to contribute a couple dollars to the project.