True. Not only do you overwork your GPU especially if it doesn't have the capacity. It takes a lot of power as well.Not $20, however I procured $2 with bitcoins mining every day. I had a good gaming PC with incredible GPU and processor. I start the mining cycle on it and in only 24 hour I procured $2. Its make me insatiable I kept my PC ON and digging for 24 hour without giving him a rest. As we probably aware mining took a bunches of intensity use, Which caused my GPU got burned and I lost my gaming PC
I think the best way is by being a freelancer, it isn't going to happen overnight, one would need to work hard at it.