My friend just got a RAZR M which are available online for $50. You can still get the Galaxy Nexus for under $100 too I believe. I'd recommend a Nexus phone because it's not skinned and laden with carrier bloatware.
I just got myself a Nexus 7 tablet the other day, any good must-have tablet apps?
I'm seriously considering a prepaid Galaxy S2 4G - but those are different than the Nexus, no? Do they have Nexi that work on the Sprint network?