I go by /~Owls values, but generally prefer FQFCs over GBCs. For example, if something is worth 1 GBC, I would prefer 2 FQFCs instead of a GBC (but I may ask for GBCs if I'm running out of boxes). I prefer doing item-for-item trades for higher-value items, but if there's something I really want, I may offer GBCs/custom :)
I also have 1:1 and 2:1 sale sections for Faerie Quest Fortune Cookies at the very end of this list, meaning some items are 1 item = 1 FQFC/2 items = 1 GBC and some items are 2 items = 1 FQFC. Yes, some are 2 items = 1 FQFC! This is because my battle pet, previously a labbie, has a loooong way to go to even out her stats. FQFCs will speed up her training, and these sales will hopefully help clear out my closet :D
BF GBCs x 21
GBCs x 2
Styling Studio Supplies x 2
Dyeworks Hue Brew Potion x 2
1 item for 1 Faerie Quest Fortune Cookie OR 2 items for 1 Gift Box Capsule
2 items for 1 Faerie Quest Fortune Cookie
Not actively looking for these at the moment, but if the opportunity arises... :)