Take that number and multiply by at least two. Smaller providers usually allow unlimited hours online for a flat rate, or give discounted rates for people who want a limited number of hours. Some providers offer a choice if you want just to receive Email, or want a full connection to the Internet. Also a few companies charge per amount of email you use, others allow unlimited email. It all depends on what is important to you.
Cost is a big factor, unfortunately there is no real base price.