I wouldnt buy one right now, prices are high. The last Iphone hype is over and more people look for Iphone alternatives, so HTC and Samsung entered the high price policy as well.
Generally I can advice you to never buy a handy with a contract. I have for 3 years now a Desire Z which costed me $450 by the time. I paied that in full and got myself a prepaid provider. Those providers send you a sim card, which you can have automatically paid monthly, so you do not need to manually recharge it. They call it postpaid now. I have a monthly fix price of $2 per month and pay per minute 9 pence. Included in this package is a 200MB data tarif which more than suffices per month. I roughly pay $5 per month, not using sms no more. I am using the mobile for business so it needs to be reliable and it is.
When you basically would choose a contract in which you have to pay more than $20 a month, its a rip-off. I have work colleagues who pay for their Iphones $100 a month an who still have to pay for their old Iphone models. Thats a huge waste of money on just a phone. For $300 you already get a small netbook, which is easy to carry and equipped with Linux a dozens of times more useful.
Be careful with high-priced models, its a huge rip-off at the moment, cause people are stupid. Give it another year or two and this hype will end and the phones will be reasonably priced again. The concept behind every of these phones are basically powerful mikroprocessors who are able to run small operating systems. Here's an example of such a thing, this "computer" is even able to run Linux. I have one as logic for a media center at my home:
http://de.wikipedia.org/wiki/Raspberry_Pi
The raspberry costs roughly $25 and the same applies for smartphones. The most costy is prolly the display but the manufactures roughly earn between 300 - 700% depending on how high their high price policy is.
Especially do never support apple ! They are not only very costy and dont even build their own phones, but buy their parts; they are inhuman as well. Its only one month ago when there was a huge uprising in one of their factories in China. Buying stuff from them, you'ld support third world exploitation...
If you really want a phone right now, look for older models or used ones. The older ones are first generation and pretty solid. The HTC Desire is a good beginner model. You should be able to acquire one very cheaply. I wouldnt pay more than $150. Thats about what they are really worth.