If you're a beginner, there will be a period of experimentation, in other words, losses.

It me two years of losing before I could figure what worked, and unfortunately I made the biggest mistake you can make in the stock market, investing beyond your bankroll.

IMO a good starting amount is 5K and consider it tuition for what will hopefully be a lifetime of investment income.

Setting a loss limit of 4% of your bankroll per trade is a pretty conservative approach, and it's easy to carry out if you are disciplined with regard to cutting your losses short.

With 5K you can buy in 100 share blocks and get out quickly if things go sour, so you shouldn't lose more than two or three hundred per trade, and eventually you'll catch a big winner that will make of for the losses and then some.

Good luck.