The prices dropped quite a bit, 6*s went to 5* price, 5*s went to 4* price. And so on.
You can use fantasitrade.com for a quick price reference.
5* max feeders are around 2-3TE each
6*s now are extremely easy to get, just need to save a few potions from a few training events or so and viola~
Also TE to Pot ratio changed, its about roughly 10:9 or something now, just poke around '3'
There's been quite a bit Potion based events lately