Google Glass was previously only available through invitation by Google to developers and 'explorers'. Google recently announced that for one day, anyone based in the US will be able to purchase the latest V2 of the $1500.00 wearable including a frame for prescription glasses or a shade for sunglasses. The deal drops April 15th and you will need to be a US resident with a Google Wallet account.
"This isn't the same Glass you saw last April. In the past year, we've released nine software updates, 42 Glassware apps, iOS support, prescription frames, and more, all largely shaped by feedback from our Explorers. The Explorer bundle costs $1,500 + tax and includes Glass, charger, pouch, mono earbud, and your choice of a shade or a frame for no additional charge. Check out the styles of frames and shades and pick your favorite."
Then timing of this 'deal' is interesting since Google I/O (and presumably a newer version of Glass) is expected to be demoed. Google is expected to release a consumer version of Glass at a cheaper price later this year.
Source: Google