Never work in sales. Period.
"Uncapped earning potential" is such a crock of fucking shit. Sure, if you want to eat, breathe and fucking sleep at work, you *may* earn a decent wage. But if your a normal person, you'll still end up working 60 hours a week for three-fifths of fuck all.
Claiming that you have the ability to earn unlimited amounts is just an excuse for certain companies to pay you a petty base wage of 30 grand a year (before tax!).
I'd probably earn more working part-time at Maccas...