Can an activated smartphone bought from ebay work without a data plan?

[JohnTolentino]

I heard if the phone is already activated, I could use it with a SIM with no data plan, I could just use wifi. Is that true?

 

[PedoBear1]

You mite be able to but your deff gonna want a data plan espically if iits an android device... lots of backround data transfer. O and you should eat less as well