Second - Day trading is EXCEPTIONALLY risky. Prices are inherently unstable over the short term, and minor fluctuations can wipe out any profits in the blink of an eye. My advice would be don't do it.
Now, if you are still going to do this, technically you could do it with very little money. You can throw $100 into the market and mess around, and see what happens. You should be prepared to lose all of it, though. There is always going to be someone out there with more information and a faster connection - the two things you need to be effective at this. Consider reading "Flash Boys", by Michael Lewis. Some companies went to monumental efforts to let their network traffic arrive 10 ms faster than the competition, and made millions. So unless you are going to have a very high speed connection to the market, with up to date (i.e. not 30 minute delayed) quotes, you don't have a chance.
An alternative and less risky strategy is called "Passive Investment". With passive investment, you can purchase shares of a mutual fund that track a broadly diversified portfolio of investments (like the S&P 500). Diversification allows you to avoid risk.
I suggest you avoid day trading and explore alternatives strategies like passive investing.
I highly recommend a book called "A Random Walk Down Wall Street" by Burton G. Malkiel. Mr. Malkiel gives a great overview on finance and investment -- very accessible and interesting for someone just getting started!
Link to Amazon below.
I also suggest that you ask yourself the following questions:
What does money mean to you? (once you get your first answer ask why that is for roughly 3-5 more times, i.e I want money to start a business, I want to start a business to be self-sufficient and independant, I want to be independant because I value freedom, I value freedom because it allows me to help people, etc.)
What stuck out to you about day trading that peaked your interest? What else have you heard of and how much have you not experienced yet in terms of finance and investing? (aka try to increase your diversity of knowledge and learn about all of your options)
Other important considerations:
1) Find a discount broker that gives you free trades. This will help you preserve your cash. Fidelity and Schwab both offer free trades.
2) Find out how to use Stop Losses. And put in a Stop Loss on every single stock you buy. This will also help you preserve your cash.
3) Start out with small "bets," that is, $200 or $300 per trade. Not $1,000 or $2,000, like I did. This strategy, you guessed it by now, will help you preserve your cash.
The key is to stay in the game.