Commander creatures you own have "Whenever an artifact or creature you control is put into a graveyard from the battlefield, each opponent loses 1 life."
You give your clients what they want at a fair price. What happens after that is none of your concern.
Near Mint - $0.20
Lightly Played - $0.20
Played - $0.20
Heavily Played - $0.20
Damaged - $0.10
Near Mint Non-English - $0.20
Lightly Played Non-English - $0.20
Played Non-English - $0.20
Heavily Played Non-English - $0.20
Damaged Non-English - $0.10
Foil Prices
Near Mint Foil - $5.50
Lightly Played Foil - $4.90
Played Foil - $3.80
Heavily Played Foil - $3.30
Damaged Foil - $2.80
Near Mint Foil Non-English - $5.50
Lightly Played Foil Non-English - $4.90
Played Foil Non-English - $3.80
Heavily Played Foil Non-English - $3.30
Damaged Foil Non-English - $2.80