I chose Firstrade for a similar purpose, to buy/sell individual stocks of interest outside of my IRA. At the time they were, or almost were, the very lowest price. $6.95 trade commissions, no minimum balances, no min to start an account, no min trades, and no account fees. It wasn't a difficult system to learn and I've had no significant problems; there have been zero surprises or hidden fees.
The only minor glitch was learning how to sign up for reinvesting dividends.
There are some new brokerages around today with lower commissions that might be worth investigating. KingTrade, for example.
A bit OT, but I also chose Firstrade for The Boy's ESA account. The reason, the initial mutual funds I was interested in happened to be NTF at Firstrade.