This is a bad idea. Fine, you pay $10 for someone's honest opinion, but it's just one person's opinion, you really want to consult multiple sources to get a balanced view, otherwise you could make a bad decision based on another person being in a shitty mood (for whatever reason).
Plus, I find friends will be honest with you if you expressly give them permission to be, and promise not to take it personally.
But if he makes money from giving people unqualified advice on random subjects, good for him I guess.
Plus, like vlunkr said, I don't know the guy, if I wanted the honest feedback of random strangers I can already get that for free on the Internet. It's not exactly like brutal honesty is in short supply, and if you target the right places it can be articulate as well.
What kind of a stranger could give me actual answers to those questions?
I can imagine a few good (applicable) answers to someone who'd pay ten dollars to email someone those questions... but I can't imagine any answers that are actually worth than ten bucks.
/r/subredditdrama
It's full of self-righteous people who enjoy watching other people fight. On the other hand, they tend to be people who are less interested in fighting and rather enjoy engaging conversation. I've had some brilliant belief-altering discussions in there, and most importantly, situations where both parties "respectfully agree to disagree."
You just have to find the sweet spots in Reddit - it takes a fair amount of participation to finds those places (but SRD is a good start).
Pitch: Bringing experts and non-experts together, making non-experts feel bad and sucky.
(unless you're sending [unsolicited?] private messages there)