Having a wallet is effectively having a pseudonymous account to every dApp that will ever exist. Likewise, the developers don't have to store any of that information or care about auth, authorization or payments.
This obviously won't translate to everything, but it does show how some presumptions about the way the web has to work(just because it always has worked that way) are being completely turned on their head.
Buy $500 worth of ether. Download metamask. Login to opensea. Buy a cheap NFT.
Look at it as an education budget.
I'd add on though to try out some DeFi protocols as well. Using things like DEXs, lending protocols, and yield farms. Experience is the best way to learn for sure.
https://dci.mit.edu/decentralizedweb
https://berkeley-defi.github.io/f21
Find a DAO aligned with something you like. Join their discord and get engaged. It's really the wild west right now.