I bought an unlocked iPhone 5s, is it possible to still be in group chats without adding my own line to it, or does it need a actual number?

I bought an unlocked iPhone 5s, is it possible to still be in group chats without adding my own line to it, or does it need a actual number?

Via Wi-Fi you can use google voice or google hangouts (free). There are also various sips although the good ones cost money. Alternately, you can look into freedompop (free 200 min 500txt 500mb $1.99/mo for MMS-i.e.group texting unless you use a sip/google voice/hangouts via Wi-Fi) or one of the other low cost carriers like Tello.