Teens involved in a drug deal unwittingly used and accepted a fake $100 bill for payment.And that’s prompting Manteca Police to warn law-abiding citizens to make sure they aren’t duped as well.Pink Chinese lettering showed up on at least one $100 bill during a drug exchange in Manteca on Tuesday between two juveniles away from their school campus. Police warn “bills” have the markings on them for counting training purposes and can’t be used as real currency. Manteca Police public information officer Sgt. Mike Aguilar said the bills come in $5, $10, $20, $50 and $100-dollar denominations.