When you sign up for internet service a lot of companies will try to sell or rent you a modem. They will tell you that theirs is the best, or that you have to buy from them to ensure that your service works correctly. But this is rarely if ever true.
Save yourself some money and go buy a wireless modem yourself. It could be as much as half off what the internet companies are trying to charge you. And they are easy to find used too so you might be able to save even more.