I have a list of nearly 17,000. Most of them are cheap and never buy anything, but over the years I've made a good living selling products from $7 - $77 or so.
e.g. Around Xmas 2012 I sold a $9 ebook to the list. 170 copies sold.
This week I ran a promotion to the list for another book, more focused on my customer base than the Xmas one years ago. It sold 45 copies @ $9. A couple years ago it would have sold at least 75-100 if not more.
This isn't enough to even make a living.
GetResponse blames me for the messages not getting delivered to people's inboxes, but when the mailing goes out I log in to another Gmail account and it says "this message was placed here because getresponse.com is known for spam" or something similar.