Iomega 34948 USB 3.0
$41. + $6 S&H at newegg:
$35 - $75 with froogle search
two thin, but positive, reviews at B&H (discontinued) from 2011
Unable to find any spec data on Iomega site. But a duckduckgo search result pointed to this March 2010 product sheet for portable and desktop drives showing this card as an option.
less spec info at newegg than here.
Anyone know whose chip is in this? For $15 +, I'm guessing it's not NEC or Broadcom or LSI. Some of the adapter card reviews for other USB3 cards indicate that there can be significant issues with no-name chips.
If it's going to take up a slot, power line and possibly require a power supply upgrade, it may pay to wait for a similarly inexpensive, reliable card with more ports. But for what it is, if this works for you, it seems to be reasonable .