There are both paid and unpaid versions of Quickoffice Pro. I bought the pro version from handango.com after trying the free version.
Various places on the net sometimes have paid apps on their site at no charge. I'm pretty sure that the companies that make the software are not exactly delighted
. I'm also pretty sure a lot of the folks who get paid apps from them have no idea that they are downloading something they really should have paid for. I didn't figure it out initially, either, and it can be really hard to find paid apps outside of Android market.