I help at my local sling library and love carrying my little one is a sling. I'd second the advice about not spending the money before your little one is born, but I would go to the sling library before she is here so you know what your options are.
I had a Close Caboo and a Moby wrap when my baby was newborn. I slightly preferred the Moby as although it was more of a faff with all the fabric, I found it comfier. I went to a sling meet to learn how to tie it properly. We used both of these up to about 4 months. Personally I would only really recommend a stretchy type wrap for a newborn up to about this age, after then buckles may be more practical for you. (or you might get into fabric wraps, opening up a whole new world)
At 4 months I hired a Connecta, which is a buckled carrier and found that very easy, comfy and portable.
Then, at about 6 months I bought an Ergo which we are still using at nearly 2 years old.
www.ukslinglibraries.co.uk/
This is a list of the sling libraries in the UK so you should be able to find one near you.