Fry's Electronics offers the Corsair XMS2 4GB PC2-6400 DDR2-800 240-Pin Dual Channel Desktop Memory Kit with two 2GB DIMMs, model no. TWIN2X4096-6400C5C, for $49.99. This $20 mail-in rebate cuts it to $29.99. With $2.99 for shipping, that's the lowest total price we could find by $22, although it was $6 less in December. Sales tax is added where applicable. Features include 5-5-5-18 timings. Rebate expires February 23.