As of this posting, Keggle Brewing has four packs of 5 gallon racetrack style ball lock kegs for just $100.  That figures to $25 per keg, no coupon code is required.  Shipping is an additional calculated fee based on your location.  Check Keggle Brewing for current selection, pricing and availability.

Four Race Track Style Ball Lock Kegs

Also Consider: Keg Connection Keg Sales – sorted to show best selling first – flat rate $7.99 shipping is also available