I use a data capable phone (v60i) with Verizon and there is no added expense when send/receiving data. They have an extra web service that is $6 a month which is not needed. This also works great for a laptop, even OSX equipped, but is a bit slow. As far as price, depends on your estimated monthly usage. Check their site for monthly plans in your zip code.
No, no......You have to sign up for a monthly plan based on the minutes you plan to use for your cell phone. Most cell phone companies have plans anywhere from 100 to 1000 minutes a month. I know that with Verizon, with a data capable phone, you can use your minutes in your plan with no extra charge if you are sending or receiving data. They do sell a $6 add-on which you do not need if you are just using the phone to send/receive data. You will just need a data cable that is compatable for your PDA and phone. You also need an internet service provider to dial into.
I use my V60i with my Mac with a data cable. My Mac uses my phone to dial my ISP through the data cable. Verizon does not care if you are talking or checking your email with your minutes. Just as long as you pay your bill......
No matter what PDA you go with, check the internet for a cable that is compatable with your cell phone and your PDA. There is place called SupplyNet, I have never used them, but they seem like they have a lot.
I have sprint pcs w/ vision. You can get a cable for most of their phones and it does not pull from your minutes when you go online. Check ebay for the cords and the special software you need. Thinking about getting a cord for my laptop.