*Noob warning*
I have a quick question for you guys here, and I want to apologize ahead of time if I am posting this in the wrong section.

I have noticed that many sites that sell user-customizable products look very similar.
See for example:

I want to build a website with a similar functionality to that (though different products).
I like the dropbox, the dynamic pricing, the fact that different options within the dropboxes have individual details and the general layout. I can't help but notice those sites are all very, very similar.

Basically, what I am getting at is, how difficult is it to build a site of similar quality to those listed above, and with similar functionality?
Are there templates/configurable themes that would enable me to accomplish that with little coding knowledge?
Or are those pages something that only a professional could handle?

I am sorry for the noobish questions, but I would greatly appreciate any replies/help at all.