a Dividend ReInvestment Plan where the company you have invested with arranges for your stock dividends to be automatically reinvested in additional shares of their stock, most with no or low fees. Most company plans will also allow you to buy additional shares (average minimum investment is usually $100, but many companiess do so for $50 or $25) weekly, monthly, or quarterly directly from the company with little or no fee. PAYX charges no fees to reinvest or purchase additional shares.
Some companies allow you to purchase your first shares directly from the company, others require your ownership of 1 or more shares before you can enroll in their plan. It's great!