I have been amusing myself by building Modern format Budget decks ($15 or less). I figured I'd post them here as I build them, and people are welcome to request decks (for me to build) and to use these decks as their own. Anyone can fufill deck requests, just make sure that they have a coherent theme, cost less than $15 to assemble and are playable in Modern.
Also, please don't post your own decklists if you are just looking for suggested alterations - you should make a thread instead!
I've used CoolStuffInc for my prices (and it's worth noting that these prices don't include Basic Lands or Shipping).
Here is my first list:
:R: BloodThirst for $11.99