Donor deals are allowed, but the only think which is not allowed is to sell things that are not for gtm like to give Gtm money for a skin or for a irl gun or something
So if I magically multiplied my money by 13 you'd buy me the rankupgrade to sponsor? xD EDIT: Seriously though, if you have 50$ for a donor deal, can you wait a week or two until I have 12.5mil on gtm1?
To clearify, donor deals that involve GTM currency may only happen on the GTM Store. Donor deals involving exterior sources is strictly prohibited. Ex: You may not do a donor deal with someone to buy you GTA V for in game money.