It seems to be common in this recession that people run out of large business who fight over advertising space. So the companies that rely on advertising for revenue reach out to smaller businesses to try to peek an interest. Mixed in with those are people who are, deliberately or not, being deceptive in their marketing ploys.
So it's important for small business owners and hobby photographers alike to be careful and to pay attention to what is being sold. Ask questions.
Sometimes they'll say it's an exclusive deal that's just for you and if you don't commit right then they'll call the next person on the list. In this case, ask them how they got your information. If you're not a wizard with search engine optimization, it's likely that you're not the first person they called.
Ask them if the advertisement will be passive or active. A passive ad is one in which the consumer must do something to get to the ad. For example, putting a blurb about your information in a pamphlet and then displaying the pamphlet for consumers to take is a passive ad. The client must pick up a pamphlet to see your ad. An active ad is one that the consumer does not have to do anything to see. A commercial on the television is an active ad. Active ads usually generate more sales than passive ads do.
Ask them how many people they expect to see your ad. Unless a lot of people see it, it's not worth paying a lot of money for.
Ask them what other companies they advertise for. This gives you a feel for the success of the advertising they do. I would talk to some of the other businesses just to make sure you weren't lied to.
Go to the place that wants to advertise for you and look at some of their advertisements. Ask about the frequency that your ad will be shown to the consumers.
Most importantly, draft a contract that outlines the services you understand you will be receiving in exchange for your payment to their company. If they don't deliver the services as you were under the impression it would work, you have a contract that shows what was supposed to happen. If an advertising company or marketer refuses to sign a contract with you, don't work with them.