adulterate
alloy
bargain
beat down
bid
bid for
break
canker
chaffer
coarsen
confound
contaminate
corrupt
cut
cut prices
debase
debauch
decline
decry
defile
deflate
deflower
degenerate
degrade
denature
deprave
depreciate
desecrate
despoil
devaluate
devalue
dicker
distort
dive
downgrade
drive a bargain
fall
fall in price
give way
haggle
higgle
huckster
infect
jew down
lower
mark down
misuse
negotiate
nose-dive
aggravate
exacerbate
exasperate
worsen
cheapened
cheapening
cheapens
deepen