If XYZ wants to sell something for you, sign them up to your standard reseller agreement.
If XYZ (or anyone else for that matter) wants to be paid for introducing you to a potential customer, thank them politely for the offer, but decline.
Even if you manage to close business with the lead -- which I bet you won't --, you'll spend more time and energy managing the relationship with XYZ (which will sour because of your not closing a huge deal) than the lead was worth.
(Sorry if I sound jaded. Good luck.)