Used 5 gallon single handle ball lock kegs from Adventures in Homebrewing.  These kegs are pressure tested and guaranteed to hold pressure.  They also include a new set of o-rings.

As of this posting, these are marked down to just $39.  AIH says availability is limited and that they won’t have these for long. Check product page for up to the minute price and availability.

This promo has expired.  See Recent Finds

5 Gallon Cornelius Keg (Ball Lock) Used Single Handle

Also: Kegerator Tips & Gear | Keg Repair Part #s | 5 Recent Keg Finds