Sounds sketchy. How will you ever verify he closed these sales? Is there a database you(and others) input these leads to make sure there are no duplicate leads??
A lead is a prospect he will try and sell something to. You'll want to find out what kind of product he is selling, you can look up the % of leads that actually convert to sales. You wont generate 10 leads that convert per day. Maybe 10 per month.
He wants you to find potential "leads' or candidates that fit the two requirements so he can deliver his pitch and hopefully make a sale. Basically you'll be filtering out numbers from his call list, saving him time.
Sounds too much like those old "Entry Level Sports Advertising" listings in the Greensheet where you just ended up going door-to-door selling worthless trinkets all day.
I'd be really uncomfortable with the $50/closed lead pay. You may end up working for next to nothing. I suppose it's their way of ensuring you actually qualify people, but I'd expect some kind of hourly on top of that. Especially since the close is dependent on someone else! Apart from that, as others have mentioned, you're working the phones, filtering a huge list of numbers to come up with a qualified prospects list. Cold calls. If telephone soliciting is your thing (heaven forbid) there might be better stuff out there.
This reminds me of a sad point in my life. I was about 22 years old, and just got "laid off" *cough* Anyway, so I am sitting there in my "apartment" *cough* parent's house, felling depressed, when I saw an add in the Chronicle classifieds stating "manager trainees wanted, $45K/yr. to start, work your own hours, need highly motivated folks; no college degree required; etc.". I thought, "wow", this is right up my alley. So I call in and after 5 mins of talking to the head guy, he hires me over the phone as a manager trainee, stating I will be a manager in 3-6 months with 2 teams of 5-10 folks working under me. Afterwards, I feel like I am on top of the world. So I show up the next day, only to be brought back to reality by the fact that this awesome job involved going from car dealership to car dealership selling ties to car salesmen. Lesson learned? It is always too good to be true.