Can you still call and text on a outdated iphone?

I'm thinking of getting an iphone4 or 4s and an ipod touch for all my apps since the 4s will be outdated soon but can you call and text with the old phones because i know you can't download most apps but i'm thinking of getting it only for calls and texts

Yes you can, you can still do it on old Nokia phones

Of course, I konw some still use iphone 3GS today and all they do is call and text, works fine.