What do you mean by very small? It's smaller than Bitcoin.

I am not talking about large amounts. Perhaps 10-20 euros per month (20 is much to me but since I no longer need to buy food and if it's bread only, I don't smoke, have no car, I don't drink, never go out, don't need medication).

10 euros is 0.33 / day. It is doable if you want plus I think investing is on long term at least for me. For a while I checked daily wrote it down. I no longer do that. I wait for the big surprise.