I don't sell basic products anymore (factory products). I only sell storage items and items like cement, pizza, watches, shoes, etc.
I always sell for the default price so most of the times it sells fast.
However I've not been selling too much lately since I got some coin offerings that giev you much more than the market.
I sold a hamburger for around 3.3k. I sold 8 fireplaces for 14k. Now I'm farming 5 fruit cakes to sell for 14k. I've sold 13 grass for 4.4k, 1 donut for 1100.
IMO, it's more worth it to wait to get nice offers than use the market. Or mix a little. The offers are just awesome and they are not so rare.
