Before buying any component, make a list of all you need. Also, if you can't figure the list out, make a topic here in Tom's Hardware forums. We have plenty of experts around who can give you the best performance with the money you have. You might even find interesting new components that you never knew existed.
You can use PCPP to keep a list of your components which also includes lowest purchase prices, depending on your criteria,
link: https://pcpartpicker.com/list/
As far as my own PCs go, i have 3x of them: Skylake, Haswell and AMD. You can see them all from the 3x links in my signature which also include full specs (with component buying prices), story behind each PC with build logs and lastly, pics as well.
Btw, at current time, best way to learn building a PC and without risk of breaking a wallet is via a game called PC Building Simulator,
steam link: https://store.steampowered.com/app/621060/PC_Building_Simulator/
While building a PC in real life is more complicated, that game gives a good idea to anyone who doesn't know how PCs are put together. Game also includes troubleshooting on software and hardware level, though more simplified than in real life.