No Contract phone clarification

[LazyGunnit]

Ok, I'm currently using a Lumia 520 (AT&T no-contact GoPhone) and I'm looking to upgrade. Lets say I purchase a Lumia 1520 without a contract at full price. [$800] (Or any high-end phone without a contract, really)
Would I be able to use the new phone on my "pay-as-you-go plan" or am I restricted from doing that?

 

[broughshane]

As long as your new phone unlocked, you can use your old sim card . does your 520 use a micro or nano card. 1520 uses the nano now. But AT&T will change your details from 1 card to another in store.

 

[LazyGunnit]

The 520 uses a micro SIM card. I've had AT&T change my details before so that shouldn't be a problem, thank you very much! I'm looking forward to getting a newer phone

 

[RumoredNow]

Don't pay $800 for AT&T's crippled version of the 1520. Get the real deal for under $500. Nokia Lumia 1520 RM-938 32GB Smartphone A00016719 B&H Photo

AT&T charges extra for 32GB internal storage. AT&T strips out Qi Wireless Charging and you have to add back in wireless charging with a special case and a less widespread charging standard. AT&T adds in bloatware. AT&T has to "approve" updates after Microsoft and Nokia are finalized and that means more wait to update.

I just got this phone and it R.O.C.K.S.