I have a friend who does financial advices and arranges certain deals. Thanks to him I was able to make a deal on which I saved a good amount of money. Since we're not that good friends, we usually meet just for these occasions and a few others, I won't be able to repay him in other ways. He has never wanted any money from me, he profits from deals he closes and if that are periodical investments, then even a some percentage from that.
It is important to note that I would never save those money if I were a normal client of his. To imagine what kind of saved money it is - its is like being offered to buy a thing to which there is a 20 % tax. And I would be saved from that tax. (legally)
Question: How can I offer him like 30 % of the saved money (approx 40 EUR) without making him uncomfortable?
Note: many questions on this stack are closed due to the opinion based reason. This one might be one of them, but I don't really see how this stack would not be full of opinions.