I have a lot of maaser that I owe but money is tight now. Can I take on volunteer projects that I would normally charge for (pay myself the rate I charge and calculate that as maaser?) The projects I would do would be for nonprofits, mitzva causes that would normally hire someone but don’t have money to pay. The organization that I have in mind encourages chareidi aliyah- they send out a newsletter, maintain a website with open jobs in EY, and interview frum people that are living in EY.
You are allowed to do this, It sounds like this would also be considered a mitzva, and you can consider it regarding ma’aser. I general if money is tight for you, it is possible that you don’t have to give maaser at that time.