Shortchanging

To defraud someone by giving them less change than they should be given after a transaction.

"I got shortchanged! …I gave him $10 for a $5 item and he only gave me $1 back."

(by extension) To deprive someone of something for which they paid.

"The elective class was easy, but in the end I was shortchanging myself."

To make disadvantaged by design.

"Being proud of mistreating shortchanged "enemies" is a likely sign of class consciousness, as well as thinking or speaking ill of them."