Three types of magic are
Type 1(Vintage)
Type 1.5(Legacy)
Type 2(Standard)

Basically, you will not want to play Vintage because of the all the old, good and expensive broken cards. Legacy is somewhat cheaper. A decent Legacy deck won’t be quite as expensive as vintage, but more expensive than than Standard. But because you have to keep buying the new cards that come out for standard, which keeps changing, type 2 is in some ways more expensive than Legacy. Both legacy and Vintage include most magic cards, but Standard only includes the few latest sets.

If you want to be a casual player and not play in tournaments at first, then you probably want to buy cards in bulk. You can buy hundreds or thousands of cards online with $100, but the decision of which cards to buy should be based on what you plan on playing. Booster boxes, packs, and fat packs are going to be straight from the factory, and probably new and Type 2 legal. They will also be much more expensive than just buying a bunch of old cards from some collection, but that bulk card collection probably won’t have cards from the right sets to make a type 2 deck. It just depends on what you plan on playing.

Note: Buying Booster Boxes is the best choice for standard. Don’t ever worry about Basic lands, since they are dirt cheap.