Monthly internet connection costs. Question?

When i had a regular land line telephone, back in the old days, it was thru AT&T.
On their web site it states internet could be $55.00 bucks a month with automatic billing on your credit card.
That sounds pretty good with me.
BUT, there always is a but.
I have to do more research with them about their equipment required for me to connect with the internet.
Do i have to buy the equipment, or is it rented, with an additional charge each month on the bill?