My car told me it needed an oil change so off I went to the dealership today. I know I could save money doing the oil change myself but...ick. I did this when I was a poor college student, now I just want to pay someone else to do it. I did call around to oil change places when I first got the car because it needs synthetic oil and those cheap oil change places charge an arm and a leg for special oil so I take it to the dealership which has the cheapest price for my required oil change.
Fortunately, after each oil change at the dealership they email me a survey which gives me $10 off on my next oil change so it was only $30 with a coupon. When I checked in, the girl popped off the engine air filter and said it looked kind of dirty and asked if I wanted to have them change it but when they told me it would be $95(!) I declined and immediately ordered the filer from Amazon when I got home for $18. I can definitely pop in an air filter and save $75 in the process!
tldr; when it comes to car maintenance, call around for the best prices, DIY the maintenance that you are able to, and use Google/YouTube--there's info and videos on all kinds of car topics there.