To make a camera is very easy, it is just a box with a negative inside and a hole where the light can enter. That's it!
I went to a shop, bought this tin and made a hole on it. But in order to get a good image the hole need to be very small.
First I tried 2mm hole which gave me a very soft image. Then I tried smaller and smaller holes until was able to get sharp images but flare became an issue.
My camera have 100mm focal length (which is wide angle for large format). The ideal hole for a sharp image is 0.422mm which correspond to f238. I will keep trying to make a pinhole near to 0.422
I use paper negative ISO 6 which are cheaper and easier to develop. With paper negative I can make contact prints but if I want make enlarged prints I will have to use film negatives.
It will be a huge camera but bigger the camera bigger the negatives. And bigger the negatives better.
I am placing all the test photos with description in this link:
Conclusion: You don't have to spend money buying cameras. Make one. It is easy and very addicting. I like it better than my brand cameras.