There are many ways to make money while staying in Spain for non-profit. Here are some suggestions:
Private Chinese Tutoring: If you have experience in teaching Chinese, you may consider doing a private Chinese tutor to teach Chinese to locals.
Skills personal training: If you have special skills, such as musical instruments, sports, etc., you can also earn money through personal training.
Overseas bloggers: Attract traffic and followers by sharing your overseas life, and then make money through advertising or bringing goods through the platform.
*: This is a relatively low-barrier way to make money, you can find local specialty goods and sell them through social ** or circle of friends.
Become a landlord: If you have investment funds, you can buy a good quality ** locally and rent it out for a monthly rent.
Opening a bar, a farm or a snack bar: these will need to wait until the one-year non-profit residence period before switching to a business owner visa.
Keep in mind that during your non-profit stay in Spain, you can only do things that don't take away from the jobs of locals. These are all feasible ways to make money, I hope it will help you.
Spain