Cheapest option is if you already have a suit, wear the pants and shirt (long sleeve) on day one, add the coat and tie to wear for day 2. I suggest a quick iron of the shirt between the 2 days. If you don't already have a suit, find one on sale, never pay full price. Men's Wearhouse has sales all the time, yes the quality isn't the best, but you literally only have to wear this 2 days. Good luck.