i wanted to start buying and selling stock online. i’m looking for long term stock investment. in other words, i wouldn’t trade stock that often but i wanna reduce commission if possible. the stability and accountability of the trading company is a main concern too.

If you only have a small sum of money to invest and will not trade very often you could enroll in the Sharebuilder "BASIC" automatic investment plan. The basic plan does not charge a subscription fee.
The commission charge is $4.00 per transaction using the plan.
Major disadvantages: Within the plan you can only buy/sell stock on Tuesday’s. Real-time trading commission is $9.95.

I use Scotttrade.
NO account maintenance, service, or inactivity fees.
$7.00 online trading commission for stock over $1.00 a share.