Where can you convert gift vouchers into cash or sell them fairly?

Hey guys where could I e.g. Spotify, psn, xbox live, google play gift cards convert real money or sell? Are there sites that do that except now wait a long time and set it on ebay etc?

Nobody buys because of the risk of scam.

sell to your friends or find a dealer who sells it.

Thank you, and how do you find such a "dealer" who sells it?

Ask the boys at school if they know anyone. One always does it for business