Isn't having something like collateral or work that is external to the system a key part of keeping value in check?
If you engage in provably Byzantine actions, your stake can be slashed, burned, or otherwise sacrificed or redistributed.
There are Byzantine actions that one can take that are unprovable at this time AFAIK (IE: exploiting the data availability problem).
You will need to download an Ethereum 2.0 wallet when it releases and start staking through the UI. 6 or so of these are being built and you can check it Prysmatic Labs to see the progress on theirs.
One important thing to note is that the proof of stake Ethereum chain is a different chain than the proof of work Ethereum chain. You won't need the legacy PoW chain to stake.
With PoS you only need data from the last checkpoint to stake. This is only a subset of the entire chain. You also only need the data for the shards you are a validator for which further reduces the data required. The goal is to allow anyone to stake if they want to regardless of hardware in order to increase decentralization.
