Expected SEO costs?

I'm looking for a one time optimization of my site. I currently have about a dozen pages full of content and I have implemented as many of the SEO tips I've read here that I'm capable of doing. But I'll be the first to admit I'm a noob to it.

So I'm thinking about hiring an SEO company I found here. But I've never looked into it before and while I'm waiting for the quote, I'm wondering from anyone here who has paid (or charged) for SEO services in the past, what ballpark should I be looking at for price?

PS. This is a human SEO service, not software.

TIA.

PS. I don't want this to be a bidding war or anything - I've researched and chosen the company I wish to hire already.

Nevermind - found it: http://www.ozzu.com/other-search-engines/how-much-for-seo-expert-t49322.html