Starting my collection

Hey dudes/dudettes, I’m looking to get into collecting cards and was wondering what the cheapest/best way to start collecting would be? I’m looking on Walmart but I don’t know what’s worth spending money on. I know I can go on eBay for specific cards but not looking to do that at the moment. I miss the feeling of opening up a pack of cards when I was younger and never knowing who you’re going to get in the pack

I’m interested in all teams but I’m a Red Sox fan and also would love to start a collection of rookie cards / vintage cards as well