Too Many Leads!!!

[TIME]

Guys I'm about to have more than I can handle. Right now I get about 120 buyer leads monthly via the internet. That number is about to kick up to about 5-600 monthly, in about a 60 mile radius of where I am. I am not familiar with a couple of the areas that the leads will be coming from.
I was going to just charge other agents a referral fee.

What do you guys think is fair as far as referral fees for hot leads i.e. buy within the next month.