Honestly, just register for a year. You will have the domain and you will have a year to get your learn on. There is really nothing to be wary of.
The question I have is this. What are you going to do with the domain?
We register all our static domains through Go Daddy, so far over 36 domains. Their interface isn't the best, but their prices are. For dynamic domains use DynDNS.org.
I think I'll use it for a webpage for my private medical practice: clinic information, procedures offered, info about me... One you'll definitely want in your bookmarks!!!

It will be a few years before I could afford to build my own office, so I probably wouldn't use it much now since the pre-existing clinics already have webpages, but if I open my own office, I'd like to have the best domain name I can get now while a couple are still available.
One concern I was having is that if I register with a particular company (godaddy for example), after a year or whenever if I wanted to go to a different company other than godaddy (if there'd even be a reason to do so, I don't know), can I keep my domain name and change companies? I couldn't find anything about that, so I was afraid to go ahead and purchase through them in case it would lock me into always dealing with them as long as I kept that domain name, and I didn't know if that's the company to go through or not...
As far as dynamic domains... I have no idea what that means.