“Budget” can mean a lot of things with regards to decks. This one should cost about $40 right now. Luckily, Elspeth, Sun’s Champion was recently printed in a Duel Deck which dropped her price a bit.
It’s basically Mardu Removal: The Deck with essentually 20 removal spells. Mardu Charm doubles as a small threat if you don’t need removal anymore.
The primary win conditions are Elspeth and Zurgo Helmsmasher. Zurgo is fun budget smashing. By the time you cast him, your opponent’s creatures are probably all dead. If not, they will be after Zurgo plows through them. And then Elspeth is Elspeth. Tokens, tokens, tokens, oops they fly now, gg.