My experience with these 3rd party sales leads is varied like most others. Ultimately, Thumbtack worked the best for me.
After paying for a lot of leads and getting some work I went back and looked at all my leads, all my response, what worked, what didn't. I created a few rules of thumb to go by. For me this is how it worked -
Where does this lead live, if its not an area that's more affluent, I didn't bid.
What kind of computer/device are they looking to get fixed ? If it was last years black Friday special at Walmart, I didn't bid. Its not that we wouldn't/don't work on cheap machines or that I'm above black Friday Walmart specials ( please don't hear me being snobby because I'm not) its just that my history with thumbtack showed that the people that put out requests with cheap disposable computers were tire kickers.
What time did the request come in, people that put out the request during daytime hours were more likely to hire me, the late night ones, I never herd from after the bid.
I also looked at the wording of their request. If they spoke like a tech, I didn't bid. Because they where probably a tech shopping the competition or they are the I know everything client... you know the one, they come in tell you whats wrong and how to fix it, question everything the tech does, tells you how handy they are with computers and you just want to say to them if you know so much, why are you hiring us?
In looking at my responses I also realized that on responses that I started out selling why we are the best choice, how educated and experienced our techs are and on and on, I didn't get jobs but when I started out talking about them, their problem, their solution, what day time works for them then mentioned our credibility stuff, I had much greater success.
Looking at my successes and failures helped me fine tune my process. I went from bidding on everything to bidding on 1 out of 10 but I had great success getting that 1 client and they were a good client.
From about a year with thumbtack I picked up about 4 businesses that have used us 2 or 3 times for break fix and a few residential that have been return calls and given referrals. One of the residentials was well out of my normal service are, I quoted him $20 an hour over my normal hourly. He has had us in 4 times for various jobs, one of them being a $1,600 job.Also, those are customers that wouldn't have found us organically.
I think the key with the 3rd parties is weeding through the 75% crap to find the 25% that's worth it. Once you figure out how to make Geekatoo, Thumbtack,Work Market or any of them to work for you and not, you work for them, it becomes worth it. I don't go after a lot of 3rd party stuff any more but our first 9 months to a year, I'm really glad we had it.