In that case, you could have easily found the job without the agency, for free. Last, any company that will give the job order to an agency to find the candidate and expect the candidate to pay, isn't a good company to be working for. Companies who don't want to pay a fee will do their own advertising and have their human resources department handle the incoming resumes, set up the logistics and pre-interviews and do their own reference checks. If they want an agency to provide that service, rather than use up the time and resources of their HR department, then they should foot the bill and not expect you to pay for the service they are using. If they do, that tells you something about the company.
Most states have very good employment offices and a lot of information.
Learn as much as you can about a company before the interview or even before sending a resume. Gear your cover letter to the specific company. If you're too general, it sounds like fluff. If you have a question I might be able to answer, my addy is above. Midge, thank you so much for all the advice.