Would it be better for me to pay to use an online company like e-trade or ameritrade & pay the $10 per trade fee - or to direct buy stock (DRIP) from the company if they charge a $7.50 registration fee & a $0.15 per stock fee when you sell?
l am looking to only invest a couple thousand & plan to let it sit for like 15-20 years without touching it.

(DRIP) e-trade or ameritrade will charge your account inactive trade fees that would empty the account in 15-20 years. You can buy several DRIPs through one stock transfer company. http://amstock.com/main/

Yes, the Dividend Reinvestment Plan.

You can also look into no load mutual funds.

Tradeking and Scottrade have lower commissions and no inactivity fees.

With http://sogotrade.com , you get cheap trading commissions at $1.50-$3.00, free research tools for stock trading, an efficient and robust platform, fractional shares and DRIPS.