I actually made a character backstory based on the cost of a spell.
Khale Darin was a rogue. His best friend/partner/love of his life, was a fighter Mara. The pair went into a low end dungeon seeking a bit of coin and experience. In that dungeon she was killed and Khale had to escape with only her sword, a bastard sword, and some of her hair. His reason for adventuring was to get the money together to have her resurrected.