What can I do with a deactivated iPhone 4?

Can it still use Wi-Fi? And can it still use iMessage, but from my apple ID now (instead of my phone number)?

Yes, the iphone 4 and newer use Wi-Fi technology. And iMessage uses Wi-Fi. So basically now you just have an iPod instead of a phone. You will still be able to use your apple I'd and buy songs, apps, etc. You will be able to use iMessage as well. Hope this helped. Have a good day!

Sell it and say it's brand new.

You can still use over Wi-Fi and you should also be able to use iMessage with your apple ID.

You can use it as a ipod touch and do everything they can do.
if you need a new iphone, email me i have a few for sale or trade

Is there any way I can get my old Iphone4 not 4s or4+ to use Wi-Fi I try but its blured out white