Avoid driving a car.
But if you must, fix and maintain it yourself. Most libraries have Haynes or Chilton repair manuals, and even more information can be found on the internet. Useable tools are cheaper than you think (craigslist and the pawn shop), and should you need a specialty tool, call around to the parts stores and local shops, some will rent out tools for very cheap.
Parts stores have accounts for wholesale customers that are automatically set up with discounts attached. If you happen to work at a place that has one of those accounts, most stores will allow you to use the discount on the account, but pay cash instead of charging to the business. If your employer has any sort of a self maintained fleet, maintenance shop, or even in house grounds keeping, they probably have an account set up somewhere. Find out where and use it.
If you don't work somewhere with an account, pick a single parts store and get to know the people working there. Most parts stores are effectively also hardware stores, so buy everything you reasonably need from them and remember the employees names. Eventually ask to set up a house account, generally those come with a little discount and the employees with be much more likely to give you deals or alert you to sales, etc.
Also, always ALWAYS ask if there is a cheaper option. Chassis parts (ball joints, etc) are a good example of this. There will generally be a name brand, and a store brand. The name brand often comes with a lifetime warranty, where the store brand only comes with a one to five year warranty. Ball joints are a common seller, but even on the worst of cars they will typically last around 75,000 miles. The name brand will generally cost at least twice as much as the budget line, so if you are repairing the car yourself, you would have to replace the part 2 more times before the lifetime warranty would matter. Budget parts will meet the manufacturers quality, so if you got 75,000 on the first one, you can expect to get 75,000 on the replacement as well. Therefore, the car would have 225,000 miles before you bought the second replacement and the Moog part made sense. Even at 10,000 miles per year (27 miles per day average) it would take 15 years before you saved money by paying double for a longer warranty.
Now, to shoot a few holes in my argument, this does not account for inflation, and is only valid if you are not paying labor. But, it also does not account for the interest you can earn on the difference over the 7 years before you spend the other half of the money (hopefully more than inflation), and you should DIY the repair anyways. The big one is that you are effectively gambling that the replacement parts will in fact be as good as the original, and this is where you need to use some judgement. Try and establish how and why the part failed before going in, if a bolt is sheared, make sure that bolt on the cheap replacement looks well made. Many times if you compare the house line to the name brand, you will find that the parts are the exact same design, sometimes made by the same company, and I have even seen the house brand part stamped with the name brand logo.
