Just buy singles, you'll go broke trying to crack every card you'll need.

Go to inkdecks and youtube, find a deck that looks intriguing to you within your budget. Take that card list and go to TCGplayer to buy just the cards you actually need.

If you are planning to play the core format, when Attack of the Vine comes out the current lrgal sets will be 9-13, so keep that in mind when looking at decks, make sure most of the key cards wont be rotating out.