A couple problems you might run into, if you try to use this coupon code (depending on your location, and your cashier).
1. Michael's says it's only good on regular priced items, but when I tried to buy an item on sale with this (a shadowbox), AND said I'd be willing to start out the sale at regular price (before applying the coupon), I was told that the max they would take off for a sale item was $5, and they couldn't adjust a sale price back up to a regular price to make the coupon work.
2. Even when I used regular priced items, it still only wanted to take off a maximum of $5, even though my items came out to just over $25 (an $8.99 item, a $9.99 item, a $4.99 item, and a $1.29 item). She had to do an override on every item (took off $10 from the $9.99, $5 off the $4.99, and $5 off the $8.99), then scanned the $1.29, and scanned the coupon, which took off $5 more.

Total price of my items, after coupon? $0.29!!

The overrides actually helped me, because this coupon is supposed to take off up to $25, but still make you pay the tax on your pre-coupon total (according to what they told me, when I went in the store and asked). With my sales tax rate of 8.25%, I should have paid $2.08 with tax.but it only taxed me on the $0.27 charge that was remaining after the overrides!

^ you got lucky for sure but did you look at the coupon linked? It actually is a $5 off coupon not $25 and only one coupon per customer per day.

I read the terms on my coupon, and it said "spend $5, get $5", up to a maximum of $25 (down in the fine print, on the right hand side, is where the $25 limit was).

Looking at the linked coupon, it seems they might have changed the wording in the fine print, once someone realized the coupon was saying up to $25 limit. Guess I got lucky, by printing early!