Ask HN: What do you need to get started in stock trading?

[eliot_sykes]

I'm a stock market skeptic, but am becoming intrigued, mainly due to the number of stocks-related posts I've seen on HN recently.

What do you need to dabble very lightly with little expense in the stock market? Is it different for high frequency trading as mentioned in http://news.ycombinator.com/item?id=1466539 ?