Sincerity Trading via eBay offers the SanDisk 128GB Ultra Class 10 UHS-I SDXC Card, model no. SDSDUSC-128G-AN6IN, for $47.19 plus $1.90 for shipping. That's the lowest total price we could find by $6. It features read speeds of 80MB/s.

Note: This ships from Hong Kong and may take two weeks for delivery.