Hi @Flo You first have to decide whether the inherent risk of using non-ECC RAM is for your use-case and needs. Let that drive which hardware you go with. Which is to say, if you hedge and go for non-ECC RAM and you experience an issue related to RAM error that would've been corrected with ECC, you're going to kick yourself. If that's true, then wait until you can afford that additional cost. If not, and you can live with the added risk of running non-ECC, especially with some of what the new chipsets offer, go with that.
There is no magic here. Just your ability to honestly determine what you're needs are as measure against your risk tolerance, timeline and budget.
Good luck and welcome to the fold!