You'll be your own boss
If you're a good wedding DJ, you'll soon find yourself in demand. Many of my gigs lead to others (weddings are usually full of engaged and soon-to-be wedded couples), so you should always have a pocket full of business cards. Though you might need to rent your equipment at first, in just a few gigs you can make enough money to buy a high-quality mobile setup. Then the rest is up to you - the more you put into marketing yourself, the bigger your income can get.