The build I put together is a 90mm Brushless build for around 50 dollar, depending if you bought parts in sale or not. If anyone found parts that are even more cheap than this build id love to hear it, and ill update this page!

This Build is without FPV. If you also would want FPV you could order:
https://www.banggood.com/Eachine-TX01-Super-Mini-AIO-5_8G-40CH-25MW-VTX-600TVL-14-Cmos-FPV-Transmitter-p-1088374.html
PRICE: 10 Dollars

Or

https://www.banggood.com/Eachine-VTX03-Super-Mini-5_8G-72CH-025mW50mw200mW-Switchable-FPV-Transmitter-p-1114206.html
https://www.banggood.com/600TVL-8_0MP-14-2_8mm-CMOS-FPV-170-Degree-Wide-Anlge-Lens-Camera-PALNTSC-p-984345.html
PRICE: 12$ + 6$ = 18 Dollars

OR
https://www.banggood.com/Eachine-TX01-Super-Mini-AIO-5_8G-40CH-25MW-VTX-600TVL-14-Cmos-FPV-Transmitter-p-1088374.html
9 Dollars

If you want to go 3s and split escs buy these:
https://www.banggood.com/Tarot-TL300G5-6A-2-3S-BLHeli-Brushless-ESC-Supports-OneShot-For-RC-Multirotors-p-1049715.html
PRICE: 5$ x 4$ = 20 dollars

But you might have the problem that you cant power up the FPV gear.

Update:
This stack will provide a better FC and ESC for a really cheap price, making the total cost around 40 Dollars (without FPV).

https://www.aliexpress.com/item/Super-S-F3-Flight-Control-Integrated-Betaflight-OSD-2S-Power-Supply-ESC-Super-S-BS06D-4/32817527793.html
PRICE: 21 Dollars

I ended up using the FS-A8S as a receiver but I think this one would also work:

https://www.banggood.com/Flysky-FS2A-4CH-AFHDS-2A-Mini-Compatible-Receiver-PWM-Output-for-Flysky-i6-i6X-i6S-p-1214269.html?rmmds=search