I was playing R & F before release, just to get back the feel for the game. I was buying Open Borders from everyone for 1 gp for 30 turns. And I was thinking, "Dang! That's cheap!" Then I started playing GS and discovered that ALL of the AI leaders were willing to sell Open Borders for just 1 gp grand total... and realized that I was overpaying in the pre-GS game by a factor of 30.
So that low, low price is actually nothing new.
I should also mention that in the pre-GS game, AI leaders would come around offering something like 2 gp for 30 turns and 18 gp in a lump, for just ONE Salt. But then, I started to see if they would be willing to pay more.
The answer there was, "Yes." To the tune of that ONE Salt going for 37 gp per turn plus another lump sum of 43 gp. BIG difference between offered and willing to pay. One leader even paid me something like 130 gp for 30 turns plus 103 gp for just two resources.
I don't think that GS's trade game is broken. I think the entire Trade system is broken.... and has been seriously broken all along.