I'm a light gamer, so why can't I build something much cheaper?

I've noticed motherboards from $60 to $250 and cannot understand if
this is needed if you're a light gamer and manly use apps.

I might play a game once a week at most frequent.

I'm wanting to know if it's possible to get a powerful number
crunching computer for a low cost with this gaming under
consideration?

I do a lot of photo editing [no animation or 3d modeling] and use
programs to encrypt, encode and compress a lot.

So, is it possible to upgrade to a modern system for cheap?

p.s. I've built systems in the past if that helps.
ALSO I won't need things I already have like the monitor, keyboard &
mouse, hard drive.
I'm looking for motherboard + case + ram + cpu + video card basically.
thank you.


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