money.gift - kind of make sense, mid xxx - 1k for end user, but I feel probability of resale very small at any given year for this commbo, not sure this is going to be profitable
pay.promo - I like how it sounds, but not sure about who the end user would really be - without active promoting your .promo domain, probabilities of resale is very low atm. Well, this is type of name which can sell for few thousands USD in case someone likes it and wil find a use for it. On the other hand, string paypromo it is available in all other extensions like .net, .info., .org, .us..it is registered only in .com, which brings probabilities sharpy down. So in short, it can sell for 2-3K, but it is very very unlikely.