Magic sets are broken up into blocks; sets that are mechanically related to each other. Kaladesh block, for example, includes the sets Kaladesh and Aether Revolt. Both sets are focused on artifacts and energy counters.I've been playing the IOS game for the last couple of weeks and am thinking about getting into the real thing. Are the cards in the sets they release "balanced" in that I could buy a box of boosters from the newest set and have enough cards to make some interesting decks or do you really need to have a combination of several sets to do anything cool? Trying to figure out if it is better to just buy one booster box or a hand full of boosters from the last couple sets.
For playing casually, just building with cards from a single block should be fine for building fun decks.
If you're looking to play competitively, you're going to want to look at the different formats:
Standard is, essentially, the last two years worth of major releases. Standard rotates, so once a year, old sets stop being Standard-legal as new sets are released.
Modern includes all of the major set releases from 8th Edition (2003) and onward and doesn't rotate.
Legacy and Vintage include cards from all releases (1993) and don't rotate.
If you're looking to play competitively, buying individual cards is going to be a lot easier and cheaper than buying sealed product.