Short explanation: Use Arcades, the Strategist to make walls attack, and use Tetsuko Umezawa, Fugitive to make those walls unblockable.
First off, regarding the cost of this deck It should be noted that the price fluctuates, but listings on this site place a value at approximately $80 for this deck at time of construction. To some this may be considered "budget," particularly in the context of modern format, while to others it may not be. I will leave that decision to you. My main factor in noting this as budget is my rudimentary mana base, which relies on mostly basic lands. Upgrading in this regard would make this a much more viable deck, albeit increasing the price by approximately $300.
This is a really simple take on a modern bant defender deck that centers on Arcades, the Strategist. I find High Alert to be a solid plan B if I can't find an Arcades, though thanks to excellent draw power from Wall of Omens, Wall of Blossoms, and Wall of Runes, I almost always have one of them when needed. Relatedly, I find High Alert superior to Assault Formation despite its higher CMC, due to the effect being static and not requiring constant mana input to make viable attacks.
A card I find indispensable is Collected Company. This deck is approximately 50% creatures, and it can pull all of them, with the single exception being Arcades. In short, it can make for a big play that pulls the exact pieces needed without disappointment.
Finally, one of my favorite elements of a defender deck is the inclusion of Tetsuko Umezawa, Fugitive as a win condition, as it makes all attackers unblockable.
This deck can be surprisingly aggressive, especially when Tetsuko comes into play. I recommend giving it a play-test to see just how much damage, often unblockable, can be dealt by turn 5-6.
