In general, if you plan on buying singles or building a deck, it is almost entirely worth it to buy singles than buying booster boxes. Buying boxes is great if you just like to tear open the boosters for fun or want to play draft with friends to add to the box's value. It is even not uncommon for a booster box to not cover its MSRP if you decided to sell it as singles.
For more info, I would recommend watching Tolarian Community College Youtube channel. There are some great videos which would be helpful for you, such as Is it worth it to buy a booster box? in their Is it worth it to buy Magic channelplaylist, or Booster Box Game in MTG Crack-a-Pack playlist.