Fractional share buying allows investors to purchase a portion of a share, rather than having to buy a whole share. This can be an attractive option for those who want to invest in high-priced stocks or diversify their portfolio with a variety of stocks, but may not have enough money to buy a whole share of each one.

The amount of money needed to start investing in stocks in South Africa with the South African rand and consider fractional share buying will depend on the platform you choose to use and the stocks you want to buy. Most platforms that offer fractional share buying have minimum account balances or initial deposit requirements, which may vary.

For example, EasyEquities, a platform that offers fractional share buying in South Africa, has a minimum investment amount of ZAR 100 (approximately USD 7) for its fractional share trading feature. This means that you can buy a fraction of a share for as little as ZAR 100, depending on the price of the stock.

It is also important to consider the cost of buying and selling fractional shares, which can vary depending on the platform and the type of account you have. Most platforms charge brokerage fees for each trade, as well as other fees for services such as account maintenance and data feeds.
In addition to the costs associated with buying and selling fractional shares, you should also consider the amount of money you need to diversify your portfolio and manage risk. It is generally recommended to spread your investments across a range of different securities, rather than investing all your money in a single stock or sector. This can help to reduce the impact of any negative events on your portfolio.
Overall, the amount of money needed to start investing in stocks in South Africa with the South African rand and consider fractional share buying will depend on your specific investment goals and risk tolerance. It is important to carefully consider these factors and consult with a financial advisor or professional before making any investment decisions.