I applied for and received (although I still have to complete my visa process here in Madrid) a non-lucrative visa. You are not allowed to work in Spain, that is, take a job physically in Spain that potentially a Spaniard could do. I do freelance writing for U.S. companies online, and have no intention of skirting the law. My visa explained what I do and I had read that others have done the same kind of work when receiving this visa in order to still have an income. But the main thing they looked at was my savings. You have to prove a certain level of income coming in, or that you have the money in savings to qualify for this annual visa. The threshold for income I believe is 24,000 Euro/yr, but if you need to show savings, it should be some multiple of that. Of the cases I’ve heard, at least three to four times that amount.