Secondly, You can ask these questions:
“Do you implement geo-tagging?”
“Do you optimize code as well as content?”
“How many terms will you optimize my site for? and do I get to decide what those terms are?”

They should answer “Yes”"Yes” and “Depends on whether you want a short tail strategy or a long tail strategy but either way, yes you will have the opportunity to decide which key terms we will optimize for.”

Unfortunately, the answer to you question about cost is not as easily answered. There are no standards in the industry. What you should do is investigate RESULTS from previous clients. If they have a good success rate, clients are happy, etc. then pay what they are asking.

Generally speaking the cost of optimization depends on the scope of the job. Here are the factors I consider when developing a quote:

1. The industry the client is in (some industries are VERY competitive)
2. The size of the site – are we talking 10 pages or 150? AND how many NEW pages will have to be created to meet our goals.
3. Are we going for a shorttail strategy? (a highly focused list of well-researched key terms) or a longtail strategy? (a very broad list of well-researched key terms)
4. Are we going to optimize the code as well as content?
5. How much of the content can/will the client be able to generate?

I don’t hard sell. I will always be honest about your website; sometimes brutally so. I don’t JUST optimize. Like a “Wholistic” doctor, I look at the complete picture of your website – industry, target market, design, usability, functionality, keyterms, social media opportunities, etc.

My primary motivation is “How can I help your business grow?” … and sometimes, optimization is NOT the answer.

I didn’t realize that there really were professionals, because I’ve only spoken to really aggressive sales people.

How do we know if a company is legitimate and approximately how much does the service cost?