A lot depends on what you want to do One. And how good your eyes are too. Smartphones come with internet access. My Droid (the first/original one) costs me $40 for telephone and $30 for data and there is no option to just use it as a phone. So whether I surf the web with it or not, I'm paying at least $70 a month, more if I want more minutes talk time.
If your eyes are good and you're just doing light surfing that might be all you need. There is a way to make the phone's internet connection available on your laptop but the legalities are murky - Verizon says they have the right to charge people that do that an insane amount of money but
afaik noone has had to pay a dime yet. (of course I would never do such a thing because I try to stay squeaky clean at all times) PM me and I can get you going with that but all I know is Droid on Verizon so your mileage may vary.
For more serious usage I like Sprint. I've got their aircard and for about $60 a month it's not a bad deal.