Who should play this stock market?
I advise those who had amassed some NPs (about 300k) to start playing. This is because this is a game of patience, not risk venturing. As long as you keep the stock, 1 day it will rise. To have patience, you should have enough NPs to faithfully buy the 1000 shares (capped at 1k) every day. If you are a person who are not that rich yet, most probably you can earn more $ using the NPs you have, in other areas such as shops or trading posts.
When to sell the stocks?
When I start playing the stock market, I buy at 15 and sell at 20. As time goes by, I amass more NPs, I start to wait longer for the price to rise. Right now, I buy at 15 and sell at 50 and above. My point is when you are richer; your risk tolerance will get higher. Thus as to when to sell it – will have to depend on your riches and liquidity needs.