Just give him the vendor info. You are not a var/reseller/rep, so you are not supposed to be making money from referrals anyway. One of the golden rules of good business is: only charge people for exercising your profession. If you do some little piece of work that is not your regular business, then it is a favor.
Really? So no material markups, or sourcing any industrial items for clients who dont have accounts with those suppliers, and all consulting must be bad?