Well Patriot, I can answer ALL of your carwashing and detailing questions. My parents have been in the business for almost 30 years and I have grew up in and around it. I also help them out everyday!
Ok, so first of all DO NOT do it by hand at home. The salt, dirt and grime that are on your car need to come off by pressure washing. Also the soaps that you can buy in a store are NOT powerful enough to remove film or salt chemicals from your car. My parents use extremely expense high end soap to efficiently clean vehicles without hurting the body. If you handwash it then all you are doing is rubbing that dirt and salt into your paint and creating light to deep scratches. It is imperative that you keep your car's undercarriage clean in the winter. The salt and chemicals that they put on roadways is extremely harsh to your cars body and undercarriage.
I know you are afraid of automatic carwashes, but really you shouldn't be. Try to find one like my parents have which is a Touchless and Treddleless(sp?) carwash. That means nothing will touch your car, and you don't have to drive onto a ramp of any sort. You basically pull into the bay and a laser measures your car and how you are positioned in the bay to give you the most upclose and best washing. Really ANYBODY can do this. If you can park your car you can so easily do this. Also make sure that the automatic you go into it offers the undercarriage washing. That means, when you enter there are jets that blast the underneath of your car. The best carwashes do that with hot water and good soap. This method of washing should cost between $3-$10.
The other option you have is what some pp's referred to, the Self-Serve Carwash. Here you would drive into an open bay and handwash the car yourself with a wand. I caution you though, DO NOT use the foaming brush UNLESS it is made of real boar's hair and you do the following two things: #1 wash your car thoroughly with soap FIRST, #2 wash the head of the foambrush out with your wand with soap. I see so many people come in with extremely dirty cars and the first thing they do is use the foam brush on it!!
All that is doing is rubbing the dirt and crime into your paint!! I have seen a beautiful black BMW come in and do this, and try to sue my parents for the scratches. But, the sign clearly states to wash down your car FIRST. Also, something people dont' know is that the foam that comes out of a foam brush is actually NOT cleaning your car. It is simply a lubricate to help glide the brush over your vehicle.
This method should cost between $1 to start and then add coins as needed. Probably around $3-$4 total.
A couple of tips:
1. In the winter after a carwash please use a drier (if available). This will help prevent your car's doors freezing shut on the way home. Another thing you can do is open and close your door on your way home at stop signs and stop lights to also prevent freezing.
2. Do NOT touch your vehicle's body/paint unless absolutely necessary. A carwash with good soap, hot water, and high pressure should sufficiently clean your vehicle. The only time you should touch your paint is when a film starts to develop. If that happens then first throughly clean your car then use a GOOD sponge or cloth to clean. Be sure and lubricate also to help it glide across the paint. Try to refrain from using swirling actions.
3. Do NOT use an automatic carwash everytime you wash your vehicle. This will end up developing a film overtime. Also do not use wax everytime you go in a automatic or self-serve wash. And don't expect a $10 automatic carwash to clean your car that hasn't seen a carwash in 6 mths. It just WON'T clean it. You will need to wash in the self-serve bay.
Ok, so PLEASE let me know if you have any more questions. I know all about Carwashing like I know back of my hand.