The problem with buying/selling shares is the high-ish broker fees that comes with buying/selling shares IMO.
I pay $29.90 a trade which I think is quite reasonable. Compare that with property and what you pay a real estate agent!
Depends on the amount you are investing, as I think $30 is the min rate. But I can imagine it can add up if you are diversifying across a lot of stocks. If you are a trader though, and regularly buying and selling then I can imagine it can quickly add up. But in investing long term, then you only pay it twice, once when buying and then again when selling. I would have thought that with automation and computerization, that would have come down a lot in price.