I wouldn't call that overpriced. Aside from just a piece of hardware, you also get the whole new-device deal with box etc. as well as free support, warranty and a clean serial/id/iCloud/IMEI/MAC combo.
Swappa operates a IMEI blacklist checker free as a public service: https://swappa.com/esn
Just wondering why the blacklist wouldn’t be public to begin with - the blacklist would be the most effective only if anyone can check it free of charge.
"Sorry, this service is not allowed in all countries."