One of the most common and easiest things what you must do, is regularly change your car's air filter.
Why?
Well if you wont, for start your car will consume more fuel and it is exhaust gases will be more toxic, to avoid that, replace your car air filter!
How to do it and what do you need?
First, you will need car :D and of course a new filter (I don't recommend to use the old one, even if you will clean it thoroughly)
Usually those air filters do not cost more than $10, but it depends of brand..
Any way , you will need tool to open it, just scr3wdriver (+) and THAT IS IT!
Check my video where I am showing you how to replace just by yourself the Renault Megane 2 air filter ( youdon't need to be very experienced) within just a few minutes and by DIY you will save some money and learn some new skill!