unlocked phone can i use both att and tmobile sim cards

[Guest klevermind]

If you got your phone unlocked already who did you use to unlock your phone? if i unlock my phone can i still use both tmobile and att sim cards in my mpx200 if i keep both services? Like put my att sim in for phone minute use, then switch to my tmobile sim for the unlimited data.

[Guest smeg36]

I used the cheapest unlocking service on ebay, which was $9. Yes, you could use both SIM cards if you want. Just swap them whenever you want.