How should i ask my mom this?

so today im going to ask my mom to run me down to marshalls before work to buy me the chi original flat iron for 59$. we dont have to much money but im getting straight A's and i do my chores like im told, and im never really happy because it takes so long to do my hair and she said she wishes she could buy me the chi because when i went and had it done at a salon it looked great! but im just wondering how should i ask her like i should i start? any ideas? thanks in advance:)!