I think (although could be wrong) the OP meant that, in their line of work, where they may be suggesting multiple brand names, the next logical step for the buyer would be to register that brand name as a domain name. The seller could therefore say “If you’re going to buy a domain via GoDaddy, use this link” which would be their affiliate link.
It’s an interesting question, as I don’t know off the top of my head whether this would be against the TOS. All you’re sharing is a link, no personal details, and Fiverr have their own referral programme which works exactly the same way. Fiverr would not be losing out on any business (they still get the original ‘Brainstorm’ income).
@climaks - I’d suggest running it past Customer Support. It sounds to me like one of those situations where it will either be absolutely fine, or it will get your banned! So if it were me, I’d seek clarity.