Domain Name Registration

Can someone explain to me why it is that domain names cost either...
< $10 a year
or
$35 a year

What's the difference?

Also, you gotta look at the features they offer.

I'm sure the more expensive domains offer shit like webspace, forwarding, email, and tech support.

While the cheaper domains would only be a redirect. You'll have to find your own webspace, et al.