Yes. I am one of your number. I am one of you. I feel your pain. I know how hard it is to manage on an itty-bitty income with bills that reach into savings no matter how low your bills can be reduced and no matter what services are given up.
Agencies are the bane of your life and the bane of mine too. How many times have you been called for an "interview" then found it was purely speculative by some miserable agency? Mileage is not reimbursable by any agency. Trips to distant interviews are largely a waste of money unless they result in an actual job.
Head to CareerBuilder and its ilk and 90% of the positions are either clearly by agencies or by agencies pretending to be the hiring companies. To an agency, you are a product and that is all. You are not human, have no needs and don't deserve to be treated as human. If you're on their shelf for more than a few months, you're quietly thrown in the garbage as unsalable.
Agencies will not fit a job to you. They get a job request and look for the freshest addition to their files in order to fulfill the request. You are in their eyes, a product that goes stale quickly rather in the manner of milk left in a bottle in the hallway.
Dealing with agencies is frustrating to say the best. The best advice that can be given is simply not to deal with them unless one of your very best buddies is working for an agency and willing to help you to locate a position. Agencies are not on your side!
So, what can you do with online applications? It's not cool to give lists of people or organizations you don't want to deal with on a job application. The key is to ensure agencies don't contact you. Make a policy of blocking the phone number of every agency that calls your main number. And never ever give out an email address. I did once and had to close the account due to agency spam.
Regrettably, there is little that can be done to reduce the agency plague though it would be nice if the Almighty were to send down bolts of lightning to vaporize each and every agent in those agencies.