Have the AI always bought horses/iron for 1 gpt?

I don't know if it's because I'm more strapped for cash in the early game now, but in G&K I hardly ever sold strategic resources and I vaguely remember the AI not wanting to buy them.

Or do they just value you them less as the game goes on? That would make sense.

Either way I'm starting to value those tiles a hell of a lot more, before I'd only settle for the bare minimum that I need for my troops, but now I know I can get a decent production city that pays for itself while my capital is sending it food.

For a friend it's still the old 45 gold. However, now you can't gold trade with non-friends, you'll get a bum deal with just one resource. If you sell off a few the gpt will be proportionally closer to the 'fair amount of gold' equivalent. However, note also that this has now changed too (for some reason it's gone the wrong way, implying negative interest, but hey), so e.g. it's just under 6gpt per lux instead of the old 8.