Hey @Reyn Moran,
Firstly, current builds of Windows Server Insider don't contain the Storage Spaces Direct feature, so you can't use them to test it out. Secondly, Windows Server Insider builds aren't supported in production either, so it wouldn't be a good idea for you to run your workplace on them :)
If you've got a small workplace but want to take advantage of S2D to replace you SAN, try reaching out to local service providers in your area as you might be able to work with them to take advantage of monthly SPLA licensing to make it more affordable (however there are some requirements around using this sort of licensing).
Also don't look at the licensing as an additional cost 'just for S2D', as you're alternative is putting that same money into buying a SAN instead. When comparing the options, work out what it is you actually need in terms of capacity and performance, both for now and the next few years, and then get quotes for both an S2D Hosts + DC Licensing (yes you can direct connect 2-node setups), and for Hyper-V Hosts + Standard Licensing + a SAN and see which suits your budget better. And don't compare a bottom end SAN with S2D, unless you don't need any performance at all, otherwise it's not an apples for apples comparison.
Depending on your region, I'd recommend reaching out to DataON, they've got a range of really great S2D solutions that start very small and affordable.
