[grosjona]

>> ... as demand for a product goes up, supply increases, and price goes down

I think it is fine but confusing because it skips over some steps. A longer version might be:

... as demand for a product goes up, the demanded quantity goes up, which causes supply to increase (to meet the higher demanded quantity) which then pulls the price down (due to the increased size of the market and competition).

The net effect of this is decreased price overall due to economies of scale (since the total production volume of the product in the market is now higher).