You can also find plenty of commercial software which originally had very restrictive (and probably expensive to implement) DRM, so that's no panacea. I'd have been amazed if you couldn't find it anyway - expecting all N900 users to be paragons of virtue is being hopelessly optimistic (and the inability to legitimately get a copy doesn't help), and it only takes one person to upload it. If your program is good enough then a number of users will be happy to pay for it - whether this is enough to cover your costs or not is another matter, and one that's nearly impossible to predict (especially in such a new market).