Hey,
Always exciting thinking about a new build!
So, 800€ equates to about $887.54 (we'll call it $890, no big deal). The prices that I give were found on 2/1/2020 (so they will fluctuate)
For my rig I used:
CPU: Ryzen 3900x ($470 -- 424€)
MB: Gigabyte Aorus Elite WiFi X570 AMD AM4 ATX Motherboard ($180 - 162€) (You can get the MB without WiFi for a few bucks cheaper I think)
RAM: G.Skill Trident Z Neo Series RGB 32GB (2 x 16GB) DDR4-3600 PC4-28800 CL16 Dual Channel Memory Kit F4-3600C16D-32GTZNC - Black ($176 -- 159€)
CASE: So, for this, I actually was sold the wrong case by the store, where I bought all my parts. So I had to rig up several fans to hook up to the MB. So use your discretion on this one.
Storage: What are you looking to use for storage? I have an m.2 SSD, pretty cool little guys. You can always go with traditional SSD for cheaper if you'd like.
Let me know if you have any questions, I hope I answered some of yours.
You can total all that up and see what it equates too, maybe that'll give you an idea of what you need and you can choose to downgrade/upgrade the products as you deem fit.
Hope that helps
Best,
kXg