My experience and that of many other photographers I know is that unless you are doing work for clients, selling photographs is very hard. I've sold almost none. I know a number of people who are doing better at it than I am, but none is making real money. Selling, at least in my opinion, also imposes burdens. I won't offer anything for sale that isn't on museum-grade paper, printed with archival inks, and stored or mounted with only acid-free materials. In my case, that required replacing my printer, and I've got quite a stockpile of expensive paper.
This raises the issue of framing. I sometimes use cheap frames (and cheap paper) for prints that don't matter and that will be replaced. For prints that matter, I use better frames with acid-free backing board and acid-free mat board. These aren't cheap, even if you go for basic frames and use a good discounter. (I buy my frames from framedestination.com and have been satisfied.)