tmobile it cost $15 for unlimited text, and for the internet plan its another $20 much more expensive then the Sidekick i had a sidekick now i have the tmobile curve. I have unlimited texting but I didnt get the internet plan bcuz the phone has wifi and u can basically surf anywhere there is a connection. I do have the umlimited email, which cost $10.
You could get a nextel blackberry and use a boost sim card then internet and email is free, no text messages though but you can always email a text message (phonenumber)@teleflip.com
Check out http://www.boostberry.com and you can see what I have, I pay about $10 per month for everything.