For buy and hold (long term), I suggest
www.sharebuilder.com
Their basic plan is $4 per trade. However, these are NOT real time trades, in fact they are lumped all together for purchase every Tuesday. Which if you're just buying and holding, really doesn't matter. Also you can buy fractions of stock, which is nice if you want to buy rounded $ amounts of it.
Also, they reinvest devidends for free.