Low prices and fast shipping. The only thing you n...

Low prices and fast shipping. The only thing you need to do is make sure you are ordering the right parts to start with - returns can be a hassle. Also, the cheapest priced part they show for a specific application isn't always a good idea - it's the cheapest for a reason. Go with name-brand parts and you will be happy.
If you are reasonably educated about auto repair, Rock Auto will save you a lot of money. If you don't know what you are doing (like some negative reviewers), then you should probably pay someone else to do it for you.