As one of its daily deals, Best Buy offers the PNY StorEDGE 64GB SDXC Secure Digital Extended-Capacity Card for Apple MacBooks and Ultra-Thin Laptops (pictured), model no. P-ULTRA64U1-GE, for $49.99 with free shipping. That's the lowest total price we could find by $27. It features a data transfer rate of up to 60MB/second.

Also available from Best Buy is this similar PNY StorEDGE 64GB SDXC Secure Digital Extended-Capacity Card for Standard Laptops, model no. P-MEMEXP64U1-EF, for $49.99 with free shipping. That's another price low, also by $27. It features the same specs as above. Both deals end today.