I've found that in B2B you don't want to "pay" for referrals and that people are more likely to make them when they feel like they are providing value to their network without any selfish incentives.

Once in a while someone will ask for it and it's up to you to decide if you want to give people a discount or something else for helping you close new business. I personally think that's reasonable when asked but wouldn't offer it upfront.