You definitely get what you pay for with baby carriers. A lot of the cheaper carriers don't put baby in a position that's good for them and their poor design can be really hard on your back. If you invest in something a little more expensive right away it will be much more comfortable for you and your baby and you will get a lot more use out of it.
I would recommend starting with a wrap style carrier like the Moby. They're not that expensive and they are great for newborns. I thought it was very easy to use and I loved it.
If you want to continue baby-wearing, around 4-5 months you can switch to a more structured baby carrier, like the Ergo or Beco, or get a woven if you want to stick with the wrap style. We got an Ergo carrier around 5 months and I love this one too. It's a little more expensive but it's very comfortable and I'll be able to use it at least until DS is 2. Babysteals has the Ergo carrier every 3 months or so and I got mine through them for only $58.
No baby yet, so I can't really offer an opinion, but we have been given an Infantino carrier and I have a fabric sling style that I will probably use in the beginning to see how we like baby carrying. Ergo seems preferred by most and can be used for the longest, by everything I've researched.
Awhile back, someone posted this site where you can rent different baby carriers via the mail to see what you like (it's reasonable if you end up purchasing a carrier from them). They also have a 90 day return policy for purchased carriers and offer price matching, so If you do decide to purchase one, this might be an option to look into: http://paxbaby.com/zen/the-sling-exchange-c-44.html