I only have 50GB free on my main drive. I read that the bitcoin blockchain is 120gb and you have to first download the entire thing then you can downgrade it to something smaller. how can someone with limit space download a pruned version of the blockchain? Is it possible to put bitcoin core with the 120gb blockchain on a ubuntu virtualbox image that I can use on other computers with it pruned?
If pruning is enabled, old blocks are deleted on the fly while new ones are being downloaded.
With -prune=550 (the minimum value), you're able to run Bitcoin Core v0.12+ with just a few GB of disk space.