Yes, it is very possible to have a savings of 30-40 dollars monthly but it is really on the type of job involved and the target of the individual. If my income is limited to $50 monthly or below, it would be very unrealistic for me to think I can save such amount monthly but if I earn up to $120, it is more feasible. The act of saving money is a conscious decision and it is only when there is intentions that it can be possible. I have never been able to save up to $40 monthly, because my income is not really substantial, I have to sort out my needs.
Saving money can only be made possible when it comes with a target, there are still some people who earn good amount of money yet they find it very hard to save, some other people would prefer to invest it, rather than saving it and this is where preferences comes to play. From next month, I have a target to save $10 monthly till the end of this year so I utilize it in learning a skill online and if the money is enough, I can learn an offline skill.