I am expecting this Coleman Xtreme 70qt. cooler to arrive shortly:



Shipping free from Sears.com... cheaper than Amazon. (last week at least got if for $70) Got 3 cedar trays from Amazon for about $35. Including the cedar boxes I'm adding plus $75 in HCM beads... this is close to your budget. (you could use kitty litter for a cheaper rh source)
http://www.sears.com/coleman-70-qrt-...&blockType=G27