Instead of buying basil seedlings from a nursery, I buy one container of fresh, live basil from a supermarket. One bunch of live basil often contains between 20 and 40 individual plants; some are as tall as 12 inches.
After you get home, remove the pot and soak the roots in a shallow container of water. Start by gently separating the ball of roots into two, and then divide each half into two again, and so on, until you have separated the entire clump into single plants. Keep the roots submerged in water until you’re ready to plant. After you plant the basil seedlings in your garden, keep them soaked and shaded for a few days until they perk up and stand straight. You’ll now have a lovely, early basil patch that will last through fall and that cost you one-tenth the price of nursery basil plants.