If i get a iphone 4 (used) can it be used like new?

If I buy a used iPhone 4 will I be able to use it like its new and make a iTunes account get apps etc?

Yes. You can factory reset it so its like the first time it's ever been used.

Yes! Used mean that "outside" have some issue, like broken or just som scratch, but as soon the phone is restore (new as fabric) with all the memory available, you will able to use it as new, with all new account that you can create.
Wish you the best!

Just reset the whole phone from your settings and it will be like a brand new one and you have to get your carrier to set it up because you won't be connected to any network anymore