Having spent 45 minutes this morning with a very helpful tech rep who took the initiative to figure out how VZ's web access billing works for the Treo, I learned some very interesting things:
Firstly, it is true that you can access the web using the Treo without paying an extra monthly fee for a web access -- that is, you use air time miniutes instead. However, if you do it this way, you will have to be very disciplined to avoid running up an extraordinary level of airtime minutes very quickly: After activating my phone on Fri, I spent some time on the web Sun morning. I then put the Treo aside for the rest of the day. That night I discovered that on a that one day alone I had run up 690 airtime minutes. Fortunately it was Sun and I have unlimited weekend airtime minutes.
Concerned about the sudden huge accumulation of airtime minutes, I called VZ tech support. After a while he figured out why this was happening: Although the Treo was just sitting on the table all day long, the web page I had accessed in the morning remained open and as a result the airtime minute meter kept ticking. My understanding from the tech rep is that the meter will keep ticking if any web site is open in Blazer -- it is not necessary for the web site to be continuously sending data (like streaming audio). It appears you don't have to have Blazer "open" on the screen for the air time meter to be ticking -- they accumulate anyway.
To stop the airtime meter after a web session, you have 2 choices:
(1) you can turn off wireless web (by pressing the button on the top of the Treo) but there is a big problem with this approach -- the phone won't work until you turn wireless web back on again;
(2) you can "disconnect" from the web page by pressing the MENU button while in Blazer, going to the option pop down menu, and selecting DISCONNECT. (Phone is not affected and continues to work.)
If you have the discipline to be sure to do one of these at the end of every web session, and you don't use the web a lot, you may not need to subscribe to a data plan and the airtime minutes billing option may work for you. But the price of carelessness is extremely steep: If you fail to followup with one of these procedures after a web session, then in just one day you can rack up 800-900 airtime minutes. It took me about 3 seconds after this was explained to me by the tech rep to figure out that I needed to add the data plan.