Athletes are allowed to work during the summer months. At Ohio State, football players receive a $1600 a month stipend part of which is for housing. Apartments near OSU go for much less than that, so the rest of the money can be used for other needs (like skin art).
I looked at this a bit further and found that the student scholarship athletes can earn up to $2K a year. That isn’t a whole lot when you think about it.