How much data do I have to use on my iphone 4s?

I don't know how much data is available for me to use. Since this is a company phone I don't want to go over and nor do I have an AT&T log in.

Is there a way to check this without a having a log in? I found on the phone how much has been used. But that doesn't help since I don't know how much is available.

You should enquire from the company what is the data limit. No harm in asking that.