Subsistence farming in rural areas can be classified as the oldest side hustle. If it did not give you extra bucks while you waited for your payday, it most certainly gave you the nutrients you needed without having to take a taxi to town and buy from a store there.
This side hustle relied primarily on natural resources and had virtually no barriers to entry. A man could till the ground with a herd of cattle from his family kraal, while his wife planted maize