Currently China prohibits selling bitcoin mining equipment which is very popular, this is because of the very large electricity consumption, the Chinese government prohibits mining or selling mining machines.
But you are still very easy to make your mining machine at a very affordable cost,
let's calculate together for the cost of making a mining machine using GPU.
Of course what you need is a whole pc or windows device,
Motherboards $220
Psu 8x2 pins $280
Case $15
Ram 8gb $40
Windows based cpu $360
SSD 120gb $32
Pci Reiser $8
VGA Card/GPU 950
If you use an 8 VGA card then you need $ 950x8 = 7600, That means the total cost you spend for 1 Mining rig 8 GPU is around $ 8,555, but if you want to buy ready-made you can buy on alibaba.
If you want to produce the best, choose the best VGA card to see a comparison and your income can be seen here
In addition, the electricity costs are around 900 Watts for 1 mining rig machine / GPU 8 Vga card,
let's take an example
https://whattomine.com/gpus/67-amd-radeon-rx-6600-xt?cost=0.1
Daily income $1.48 and electricity expenses $0.29 per day
if you use 8 gpu your current income is around $11.84 load electricity costs around $3 per day then your profit is $8.84
The cost you incur is $8,555 so about 968 days your capital will return, but if the price continues to increase then it only takes about 1 year your capital has returned,