Mate at the start i had 1 playable character. All other characters had backpack upgraded to 100, as its cheap, and horse upgrading backpack.

All my chars were full of stuff i wanted to save, like materials, style items etc. Never made sense to me why i required 8 mules to play a game lol

Chances are if your low level, items wont sell on guild stores. Just decon and vendor all, save your gold up for bp/bank upgrades. If you collect a trophy from a mob, just vendor it as it will already tick off your achievement tog et it.