all of my items in my inventory are bound to me, but it costs 100 energy to unbind each 1 star item, which translates to around 8k crowns per item
but then these 1 star items are sold for 1k, so theres no profit and you end up losing 7k. so how are these people selling bound weapons? theres obviously some sort of alternative that im missing here
Keep your weapons or sell them to a vendor. The unbind fee is to keep people from hugely profiting off trading gear like they did when the game first came out.
Vendors are the tall folks with masks you can find here and there. The ones that sell items will also buy items from you (even if they're bound).
Unbind fee scales with the star level of your gear as well, with 5* items costing 4,000 energy to unbind. That's above 320,000 crowns.
http://wiki.spiralknights.com/Binding