A reseller partner sells a vendor’s product directly to their client. In contrast to the relationship between affiliate/referral partners who are involved only at the start of the customer’s journey (it gets handed off to the vendor), a reseller partner owns the whole customer relationship.
Resellers are the most complicated partners to work with, and for good reason! They give you access to a relatively limited but highly qualified audience. This is why they often require more support and enablement resources.
The payout partners receive for generating leads and revenues. It's almost always monetary, but can occasionally take the form of leads, giveaways, or marketing funds.