How often can you buy and sell the same stock?
You can buy and sell the same stock as often as you like, provided that you operate within the restrictions imposed by FINRA on pattern day trading and that your broker allows it.
There are no restrictions on placing multiple buy orders to buy the same stock more than once in a day, and you can place multiple sell orders to sell the same stock in a single day. The FINRA restrictions only apply to buying and selling the same stock within the designated five-trading-day period.
Additionally, there is no limit to the maximum number of times you can buy or sell a stock. You have to operate within the parameters set by FINRA if you're day trading, but you can continuously move in and out of a stock forever if you choose.
Again, that's not likely to work out in your favor over time. It's better to find solid companies with good fundamentals and then invest your money for a long duration.