Buy the cheapest Steam Deck and upgrade it yourself

[Mega Ultra Chicken]

This has to be said. You don't have to go for the most expensive Steam Deck model because you can open the Deck and replace the storage drive yourself later on. For instance, I bought the cheapest model at $400 and bought a 1 TB NVME drive for $133. If you're on the fence about buying a Deck, know that you have options even if you go with the cheapest model.