newegg offers the refurbished OCZ Vertex 2 Extended 90GB 3.5" Serial ATA Internal SSD, model no. OCZSSD3-2VTX90G, for $64.99. Coupon code "REDSSD933" cuts it to $49.99. With free shipping, that's $0.56/GB and a very low price for a 90GB SSD without rebate hassles. This drive features read speeds of up to 285MB/s and write speeds of up to 275MB/s.

Note: A 90-day warranty applies, although it's unclear who supports it.