asking professor to fund Master's student I am a graduate Masters student from one of the top-tier universities in the US. I have been working closely with a Professor and two of his Ph.D students on a Research Project for the past two months. I approached the Professor out of my interest, hoping to gain some research experience. I have plans of pursuing a Ph.D. in the near future, and I am totally enjoying this research experience under his supervision.  Quite recently he told me that he would add me as one of the co-authors if I completed an analysis for the work I have been working on. 

It's a well-known fact in my university that usually Masters students are not funded. I expressed my interest to continue working with him right through the next few semesters, and he replied back saying he was glad to supervise me, adding that he has been enjoying my enthusiasm and productivity. On an average, I spend ~30 hours every week on Research and to my knowledge, my Professor has a lot of funding. I was just wondering if I could request him for any possible funding, such as a standard 20-hour student worker position, if not a tuition waiver because it's very expensive here. Doing other on-campus job besides all this to manage my monthly living expenses, might get too hectic (heavy coursework next semester+research+20 hours on-campus job). I am so hesitant to ask him this, fearing that he might start thinking I have been doing all this for the sake of getting funded, which has not been my intention.

Should I just refrain from asking him about funding as a Masters student to maintain this healthy student-supervisor relationship that I have with him, or is it ok to ask him about funding me?
You might be mistaken about your professor having funding in abundance. Even if he has managed to bring in a lot of funding, he might be spending it all on research and researchers.

One possible way to address this might be to approach your professor at an appropriate time and gently bring up the possibility of receiving funding for your work. I would even leave it up to him how many hours per week should be paid.

As a matter of fact, you might mention immediately that you also keep working if there is no pay. It might seem that you will not receive anything when you mention this, but your professor might feel that it is morally right to provide some funding, and it will make the conversation less awkward.