From: http://tappedout.net/mtg-decks/100-junk/?fmt=

$100 budget version of one of modern's most played deck.

Sideboard is not included because it is entirely dependent on your meta and should be worked on in collaboration with others.

Key things to know about Junk:

The deck's goal is to play the best stuff in its colours. Siege Rhino is the best Junk card printed. The deck aims to 1-1 your opponents cards and then use the superior quality of cards to win the long game.

Abrupt Decay and Maelstrom Pulse are amazing. These are priority upgrades. Otherwise, focus on improving the manabase with fetchlands and shocks.