I have been participating in nearly all bounties by julerz12, and some other reputed managers, which means I havent participated in much bounties this year, and I could say that totally I have earned around $100, maybe $150 this year from participating in twitter and facebook bounty campaigns. Not much, previous year was definitely much better.
In my opinion, Bounty performance in terms of budget and payment to hunters has been on the decline for the past 10 months. Out of many campaigns that I have participated in (for the past 10 months), only about 5 campaigns made payment in the range of $10 to $40, while two campaigns paid in the range of $200. Most of the payments are less than $1. On the average, for every ten projects that I have participated in, five ends up being scam, or will have one issue or the other despite doing some research on the project before participating.
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From my own side here, I still make something reasonable from few bounty campaigns out there, just many of these campaigns end up being a waste of time. The last one whose signature I made over $2,000 from, was neglected by high rank members of the forum and I took advantage of it. It ended up being the second best of my bounty campaign ever. Some campaigns still worth the time.
Browsed the whole 5 pages and these are the only person that answered the question of the OP. Well, I might skip some of the answers but...yeah.
Some or most are saying "The earnings aren't that much anymore" or "The earnings from this year isn't the same as last year blah blah". I mean OP is asking for numbers and from bounty hunters only. Some of the answers are irrelevant.
Just basing with the 3 answers that I quoted, I guess we can say that you can still earn a few bucks from bounty programs and if you're lucky like the 3rd quote that I shared, you can earn 4 digits still from one campaign. AFAIK, bounty campaigns aren't worth it anymore at least for me and for others here. The time you are spending advertising them isn't paid or if it is, it's very low.