I agree, unpainted is not as difficult as it sounds. You can paint assembly line style. Use one color at a time using flat paints such as Testor's, Model Master or even some of the railroad colors. Select a color, use it for one person's hat, the next person's shirt, a third person's pants, a fourth person's shoes, etc. This helps you get several done in a fairly short amount of time. Our club has has a people-painting session for our club layout. Five or six of us worked an hour or two and produced a few dozen people to populate the layout. People had a lot.
You can find several fle***ones. Just be sure to leave the figures on the plastic sprues they are attached to. It makes painting easier. You'll have to go back and touch up the head or hat where you cut or nipped it off the sprue.
I even paint N scale figures, so far without the aid of vision magnification at age 44. But I might soon need something. There are several magnifying visors, glasses, etc. out there to help, some with lights.
I found a great deal on a bag of generic unpainted figures at a hobby shop in the Twin Cities of Minneapolis and St. Paul called Scale Model Supplies. Cost me $10 to $12, I recall.
I do occasional buy prepainted figures if they are special poses, etc., not readily available unpainted.