There is one exception to what I said above, which works exceptionally well on the lower difficulty levels, Chieftain to Regent: "Lord Emsworth Deals". However, for the GOTM these are banned as an exploit. (For the HOF, they are allowed, iirc. Spoonwood will be able to confirm this.)As for the AI paying for stuff, wel, I can imagine that on Deity they would start doing so. No luck on Emperor, though.
Basically they work like this:
- In deal A, you gift the AI all your gpt, and tie it to something that can easily be terminated. Like a military alliance against another civ you are about to extinguish, or a lux resource they are sending to you.
- In deal B, you buy back your own gpt from the AI, e.g. by selling them dozens of techs.
- Do the same with many other AIs
- Then end all the "A deals", e.g. by taking the last town of the civ, against which you have signed all those MAs.
- And voila: you are no longer sending the AIs your gpt, but they are still "returning" it to you...
Check out some of the HOF games by Spoonwood or Lord Emsworth for an illustration of the power of this mechanism. I think in one of his games, Lord Emsworth got several thousand gpt from the AI, by repeatedly applying that trick (first multiplying his own gpt, then multiplying the multiplied gpt, etc....)