10-20 at the most. Banned spaced tags are spaced for a reason and most likely always have a v1, therefore they are not swappable. Either way, this will go for 20 at the maximum.
You clearly know nothing about gamertags either. Its worth about 20$. It's a unswappable tag even if a method comes out because there's a v1. Don't tell other users they know nothing when you know as little as them.