how do you make a shirt

Hmmm....well I'm not an expert on sewing or making clothes or anything but I'm pretty sure that to make a shirt you would need to buy a pattern and the material first. You might be able to find a pattern online that you can print out, maybe, if so at least you wouldn't have to buy that. However, you would still need to the proper fabric/material, which you would probably have to buy. However, if you have never made a shirt before, or if you do not have any experience reading the patterns and making your own clothes, there is no guarantee that it would turn out right. In the long run, it might be cheaper if you just tried to find an inexpensive Supernatural t-shirt at a discount department store or something like that. I know you said you are low on cash, but even to make one it will costs you something, even if only for material and stuff like that, and if you have never done it before and buy the material and then try to sew your own shirt and it doesn't turn out right, you would have wasted your money.