Hi Jason,
I don't know what the magic or "right" number is for you -
it would take some competitive research.
I do have the perfect solution for you though.
A tiered program.
$1 per lead base
$5 per lead for affiliates that send over 100 leads a month
$10 a lead for over 1000 leads a month.
I just made up the volume tiers, don't know without research what those should be. But basically this would allow you to offer $1-10 per lead (for example), which sounds much stronger, yet you don't have to pay out the higher amounts except to affiliates that can generate that amount of volume.
Affiliates that generate heavy volume are worth more and if you let supers know they have the opportunity to make more based on volume you'll have a better chance of attracting them.
FYI tell your boss that since you are B2B its much tougher to get affiliates
PLUS since your B2b in a targeted albeit large niche - the number of sales are limited. Even if I were an affiliate I would not even join for less than 10 a lead to start off with and others think just like me. They will wonder "how many Realtors a month could I possibly reach that need a site an would sign up." Then they would think "maybe I could generate 10 leads a month and at $1 per lead make a whopping $10 a month." "Or I use my site and marketing to promote consumer products that sell like hotcakes and have a huge market and make 30 per sale and make around 100 sales a month - that's $3000 a month vs $10 a month. Which would you choose?
Sorry that's probably not what you wanted to hear -
but it may be exactly what your boss needs to hear.
