Covershield via eBay offers the OxGord 36" Wire Fence Pet Playpen, model no. PTMP-02-36, for $34.38 with free shipping. That's the lowest total price we could find by $4. It features a 64" diameter and includes eight 24" panels.
Note that new customers at Groupon can apply coupon code "WELCOME" to cut the price to $27.99