That is the worst phone that Palm has made in years, it has several issues. In my opinion they rushed it out before they had a chance to make the needed corrections. If you are looking into getting a newer sprint phone I suggest going with the new htc hero with android.
The 5 GB cap is only specific to the internet air cards not the web on the cell phones. He should not get charged for going over if he is watching it on his phone.
I would agree Verizon is the most expensive company out there depending on what is important to you in your plan I would go with sprint or Mobile. If you are looking to do some talking but mainly texting and web stuff sprint def has the cheapest plans and the fastest network