For me, leases are worth a great deal. Obviously, a lot depends on the budget of the property, the type of service you are providing and the property's leasing needs. So I don't know if you could put an exact price that would be a great deal as every property's view on that would be different. But as a general rule of thumb, in my market for example, most apartment locators charge a finder's fee of one month's rent per lease. When I started my locator service, I wanted to be competitive and I wanted communities to think "wow, that's a great deal!," so I charge $450 per lease. I've gotten great feedback from that. It's not too over the top or out of reach for the majority of the communities here, yet I'm not short changing myself either.
As far as applications, for me, they're "worth" the same as leases, if they go through. Honestly, if they don't go through, they're pretty worthless.
And for leads, I think that would depend on the amount that you plan to generate. I think the value might start to max out at some point. For instance, if you're going to bring in 100 leads in a month, $20 per lead, or $2,000 is unrealistic. That's a tricky one, I don't really know how to price it. For what it's worth, I send my leads to communities for free.