What is the cheapest cell phone and plan for qwerty text messaging?

My main purpose for having a cell phone is text messaging and I want a qwerty keyboard. What is my cheapest option? I send lots of texts so probably need an unlimited texting plan.

I talk on the phone very rarely -- mostly for emergencies. Thanks.

rumor for sprint

slate for at&t

they r both 29.99

i am all for the Blackberry Curve. I text like crazy and that's what i use. It really works well. You will love it. i suggest T-Mobile which is what i have. i suggest perhaps their cheapest plan of 29.99/month and then adding the unlimited texting feature for $10 more per month. You can get the phone for free from the below link.

http://wireless.5linx.com/mobile/?r=5linx&eid=L367329