A lot of the new hats are quite cheap, like 1-3k. The "rares" i know of are : pyramid head (10-20k); skeleton wings (10-15k); web wings (10-15k). Note that the prices are taken straight from random shops i visited.
I have seen a lot of people do this kind of thing and later regret the name. You have a higher chance of liking the name long term if you come up with it imo.
Oh...i'll consider that when i change it. Thanks!