There is a good research HIT popping up now and then from UBC Researcher (RequesterId = AJA4K9RWBTIT1). The HIT pays $1 with possible $4 bonus; takes 10 minutes max. I already got my $5 from it. You can only take it once.
I couldn't get that HIT, may be that is expired. Congrats on getting the bonus and the 1$ making a $5. Happy to hear that.