A quick search on ebay turned up several, including THIS ONE
for $72 + shipping...
Also try Kearbey RV
their everyday price is $79 and they offer free shipping... (I bought my weight distribution hitch and sway control from these guys).... And Kearbey is located in POPLAR BLUFF, MO...not sure how far that is from you, but it's the same state!!
BTW, you'll also need a tank, I looked long and hard for affordable tanks, finally found a pair of 36 gallon ones on ebay HERE