Overwhelmed by baby items?

Trying to figure out what I need, the best prices and the brands! There is so much stuff and so many variations of each thing! 
Any insight on any kind of baby items. 
My biggest question is what does a crib need, obviously a mattress but should I buy more than one? And fitted sheets but what else, baby doesn't sleep with blankets right? Like I have no idea! Also bottles and warmers and sterilizes! I plan on breastfeeding and pumping and probably supplementing with formula!