Platinum Micro via Amazon offers the SanDisk X300 512GB Serial ATA 6Gb/s 2.5" Internal SSD, model no. SD7SB7S-512G-1122, for $129.95 with free shipping. (Newegg charges the same.) That's the lowest total price we could find by $7, although most stores charge $155 or more. It features read speeds of up to 520MB/s and write speeds of up to 460MB/s.