ご注意(ちゅうい):Attention, Warning

手数料(てすうりょう):Commission, Fee

として:As

店内(てんない):Inside the shop

の:A particle, noun connecter

通常(つうじょう):Normal

買取(かいとり):[noun] Buying

価格(かかく):Price

8割(はちわり):80%

で:A particle, “at”

At the 80% of the normal purchasing price

いただきます:[verb, 謙譲語(けんじょうご) which is one of the Keigo]
Dictionary Form:頂く(いただく)
[meaning] I receive something (foods, presents, etc.) from someone in higher position.

買い取らせていただきます。:[business language] We will buy it.