I built a Midrange deck and am happy with it. Only thing I need to do is get 2 more Steam Vents and ditch the other 2 Guildgate.The Right is my Sideboard.
It depends on what you consider "Budget" Here's my deck and I'm replacing my Izzet Guildgate with Steam Vents and my Goblin Electromancers with 2 Pteramander. The Right Side is my Sideboard.
2 Pteramander
4 Enigma Drake
4 Crackling Drake
1 Niv-Mizzet, Parun
1 Ral, Izzet Viceroy
4 Chart a Course
4 Shock
2 Skewer the Critics
2 Lightning Strike
4 Lava Coil
4 Opt
3 Dive Down
3 Sinister Sabotage
6 Island
7 Mountain
2 Steam Vents
2 Izzet Guildgate
4 Sulfur Falls
2 Essence Scatter
1 Disdainful Stroke
2 Negate
1 Beacon Bolt
1 Ionize
1 Niv-Mizzet, Parun
2 Spell Pierce
1 Fiery Cannonade
1 Shivan Fire
1 River's Rebuke
1 Skarrgan Hellkite
3 Opt
4 Sulfur Falls
4 Izzet Guildgate
4 Enigma Drake
4 Crackling Drake
2 Niv-Mizzet, Parun
2 Skewer the Critics
6 Island
8 Mountain
4 Shock
2 Ionize
2 Goblin Electromancer
3 Lightning Strike
1 Precognitive Perception
2 Sinister Sabotage
3 Lava Coil
1 Chart a Course
3 Dive Down
1 Negate
1 Fiery Cannonade
2 Skewer the Critics
2 Essence Scatter
2 Negate
1 Murmuring Mystic
1 Lava Coil
1 Sinister Sabotage
1 Ionize
2 Light up the Stage