I use Godaddy to buy my domain names.  They have great introduction prices for new Domain Names but they do have huge fees if you let your domain name expire then want to still keep it. 

I prefer my customers to buy and manage their own domain name at Godaddy and do the re-routing of the DNS to point to your new website.

I learned how to do this from this set of instructions from Weebly.

DivTag has some awesome weebly tutorials like this video here.  
I am learning too  

No Sweat.  Changing your new web site to point at a domain name that you already own is a piece of cyber cake. 
GoDaddy Instructions Click Here