I've never seen this mentioned here so forgive me if it's been mentioned.

I'm 161 turns into a game which I am writing an AAR for (shameless plug).  When I realized I could hire Gara, Raline the Weaver, and Inaey for less than 200 gilder (27, 64, and 78 I think it was but didn't write it down).  I then spoke with Capitar who I'm on good terms with and traded them with a combined perceived value of 2490 (note that the players champions perceived value on the left side is missing a zero but when added to trade it appears, so 20 becomes 200).  I managed to get 67 horses, 150 crystal and 39 gilder out of Capitar for my measly investment in those champions, and it's not like I have to worry much if I should attack him later, they're only champions.

So this is probably abusing the system, but when trading on ridiculous is so horribly unbalanced in the AIs favour I'll take what I can get.