Best Buy and Amazon are both currently offering $50 credit when you purchase a PlayStation Vita. The standard $249.99 Wi-Fi model is applicable, of course, as is the $299.99 PlayStation Plus Instant Game Collection bundle. The latter option would be a good way to dive right into the system's existing library. Hmm.
There's a bit of a risk going for this deal without knowing what Sony may or may not announce at E3, but I suppose there's always a risk when it comes to buying these devices.