You will need a cage big enough for him to flap his wings, a good parakeet diet, fresh water every day, feeding cups which should always be kept clean, some toys to keep him happy and busy, some paper to keep in the bottom of his cage and the desire to give him love and attention.
Buy a big cage and place branches from trees for the bird to exercise its feet and clean the cage every week. Buy some toys and rotate them every week. Consult a vet and make list of food items that can be given. Make a comfortable environment with enough sunlight in the morning and total darkness at night.
In order to keep a budgie, or parakeet, you need an appropriate cage, large enough for the bird to climb and to hang two toys. Food is needed, optimally pellets, as they are form the base of a healthy diet. Parakeets need toys to chew and challenge them. Vitamins are not needed if a pellet diet is supplemented with vegetables.
Budgies are social birds, and are best kept in at least pairs. You will need a large aviary with perches, a nesting box, toys and grit, plus food and water.
Budgie basics include a cage, a few toys - ladder, swing and a mirror are good beginner toys. One or two dishes for food, a little variety is good. You will also need a water dish or bottle, perches, something to line the bottom of the cage, and something to cover the cage at night.
A proper sized cage, perches (often included, but wooden/natural ones are way better than plastic), seed, mill treats, gravel (for digestion), a cuttlebone, and toys. Pet stores can help you with further questions, but those are the basics. Newspapers for cage liner work fine.
Food: a seed mix for budgies, and sometimes you can give it fresh fruits or vegetables (avoid avocado). You also need a cage - 12"x18"x18" is minimum, and the bigger the better, preferably with horizontal bars. The cage needs perches (preferably wooden), a couple of toys and feeders. You also need cuttle-bone so the bird can trim it's beak.
Most Importantly, Budgie's Require A Large Cage To Be able to move around comfortably... Adding Branches To Their Cages Will Help With Excercising Their Feet.. Toys Should Be Added, And Rotated Frequently. Of Course, A Water And Food Bowl Will Be Needed, And Checking With A Vet Or A Pet Store Clerk Will Help With The Best Choice In Food...