Manual Activation, SERO

[srsizzy]

So, I did what I'm supposed to do and searched for threads about this. All of them date back to last November and December. Since then, Best Buy now sells their TPs for a ridiculous $700 (and I'm not seeing anything about them being cheaper), and Sprint has 'em for about $600 or something.

Being on SERO, I see I cannot upgrade AND get the normal 2-year discount without a lot of luck calling CS. So, I'm thinking that my only hope for a cheap (read: affordable) phone without being really tricky would be to buy an unactivated phone off of Ebay (or Craigslist) and manually activate it online. The TPs on Ebay are down to $270, which sounds just about as low as they generally get without a lot of luck with customer service.

Has anyone done this recently? Some threads say it's perfectly easy, but I'm not going to consider doing it until I'm totally sure I'm not wasting my time. Sounds like it should work fine. Get the phone, activate manually online, and everything remains the same, yes? I'm assuming the old phone simply stops working?

Also, sidenote: when your contract ends, does your plan just continue (theoretically) indefinitely? And I could just upgrade my phone manually like this whenever I feel like it?

Thanks for the help.