Cheapest I have seen so far:
Mellanox Connectx 3 En 10GIGABIT 2 Port Ethernet Adapter PCI E MCX312A XCBT | eBay
These are 10GigE only not IB.
Mellanox Connectx 3 En 10GIGABIT 2 Port Ethernet Adapter PCI E MCX312A XCBT | eBay
These are 10GigE only not IB.