Ebay Iphone 5, How to activate?

I just received a used IPhone 5 from eBay. The seller has send it to me with a sim card and not restored. So its still got apps, contacts, photos, messages etc from the seller still on the phone. Bit strange as I wouldn't want others having that info about me, possibly a stolen phone? But anyway if I want to use my own sim card to restore and activate the phone will it work or will it refuse to activate? Can someone help with what I need to do here?

How well

You should have asked for the IMEI number before purchasing and if the seller refused to give it, that is a sign it was stolen and sold for profit and they took the money and ran away already. You could factory reset it within the settings and then pop in your own sim to see if it works with data (make sure Wi-Fi is TURNED OFF), phone calls and sms. If data doesn't work or if the carrier says it's been marked stolen, you will find out.