Good, cheap yugioh competitive deck for regionals?

I'd go with 3 Machina mayhem. You'll still need 3 of the deck and 3 smashing ground as well as other staples such as mirror force, solemn and bottomless. It's not terribly expensive and wont be over $60. If you're going to regionals and want to be competitive for a low price this is pretty much the easiest option. However, don't feel bad if you get trounced by six sams. They're ****ing everywhere and dangerously good. I suggest siding 3 warrior elimination.