Just like any other advertising, you can spend very little money or you can spend a great deal. The return on your investment will vary from industry to industry and on the words you decide to use in your ad campaign. Cost will depend on your industry and how saturated the market is with similar companies. For example, if you’re a mortgage lender, advertising on the Internet will be more expensive because there are so many large companies that use Search Engine Marketing (so the cost per click to get someone to your site will be more than if you’re a photographer, for example). A per click cost can be $.20, or up to $10.00! I’ll be happy to investigate what it would cost for you.
What i can do is help you find words that don’t cost alot and are more specifically targeted toward what your business does or sells. The more specific the phrase someone types in matches your business, the more likely they will want your product or services.