1520 and straight talk

[schwabam]

I'm looking to get a Nokia lumia 1520 but I also want to use it with straight talk. Can anyone tell me if there is a certain way to just buy the 1520 outright and if it's usable with straight talk? Excuse my ignorance as I have been a bit behind on the new tech...

Thanks!

 

[schwabam]

Also, if you can point me on where to buy it, that would help too! Thanks!