I occasionally design sites for people. $3500 can be a rip off or a bargain depending on the designer and what they are doing. Unless you are dealing with lots of customization,,lots of seo, or a shopping cart with lots of items, $3500 is probably way to high.
The best value is going to come from the designer starting with a template you kind of like and modify it for your needs. Looking at Mark's site. It looks like a basic template with light customization. I can see it does have some basic seo optimization. With the year of updates, the $1000 is a good value
$3500 plus $1000 for SEO seems really excessive. Would have to know the finer details of what they are offering to know for sure.
If you are just starting out in the biz, dont want to spend a lot, and want to be able to modify stuff yourself, I would recommend going with a word press website. Find a template you like and find some one who can set it up, optimize it, and modify the skin for you. There are also lots of free wordpress plug ins for facebook, twitter, etc, or can be coded in for not too much.
Doing this, you can probably have what you want including seo for the $1000-$2000 range.