From my experience, the M-Day Sale is their best of the year. Depending on the state/city you're in, there could be long lines, and by the time you get in nothing really good is left. Just so you're clear, everything in the store isn't 95% off. It's not a giveaway, but a Sale. You will not find a Yamaha Absolute for $300. But you may find things cheaper than you would any other time during the year. Cymbals that may go for say, $160, probably can be purchased for $115 or 120 or something along those lines. You will find discounts on things like heads, sticks, accessories, etc. Keep it in perspective, they are in business to make a profit. As you all know, depending on what store you go to, salesperson may be willing to make deals throughout the year as well. I got my DDRUM anniversary snare for $112 when they cost $150. That's $38 still in my pocket! All I'm really saying is manage your expectations.
