I wish that there was a way to sell account bound items back to the store even if the item was bought with bubbles or gold. Maybe there should also be a sell back reward system such as if you sell back to the shop other people can buy it in reduced grabs for sell back items, for this to work the seller may have a reduced sell back price.

The way a sell back reward system should work is when you sell account bound items back to shop for a reduced price to receive sell back rewards you should get points to spend on exclusive items just for sell back users. There should be a separate type of sell back points for items bought with bubbles and items bought with gold, that way there is two different types of prize sections. Prizes bought with sell back points from bubbles should still be account bound and items bought with sell back points bought with gold should be just like any rare bought in grabs and have different levels of rarity.