Something of low quality. Can also include getting skimped with a drug deal.
"You're car is beat. It's a piece of shit"
Sam: "you fucked Erica?"
John: "Dude she's beat."
Sam: "yeah she's been with every guy."
"My subs are shot. They barely bump anymore. They're beat."
"I got beat today by some drug dealer. Took my money and left."