iMate offers the KEYDEX 2-Port USB 3.0 PCI-E Interface Card, model no. UG-USB720202PCIE, for $19.45. With free shipping, that's tied with out April mention as the lowest total price we could find, this time by $19. The PCIe adapter features two USB 3.0 ports and an integrated 4-pin power connector, which allows sufficient power for driving large, 7200 rpm hard drives.