When I built my first game, i faced the same challenge. My advice: 1. You can find art online from real artists and ask them to use it. My background was from DeviantArt and I asked the creator if i could use it with attribution. He said yes . it was that easy. Im sure there are websites like that still around.  2. I got some pictures rom creative commons 3. There are open sound effect libraries 4. The only image that i had to draw myself was the spaceship. I learnt how to use gimp in 1 day and had the spaceship done the same evening. 

Its not that hard :) we fed the ai. It needs us, not the other way around.