Check out this Michael's Coupon.
Here's how it works:
Buy More Save More
$10 off $30-$59.99
$20 off $60-$89.99
$30 off $90-$119.99
$40 off $120-$149.99
$50 0ff $150+
It does have some exclusions, but is good on just about your whole order, including sale items!
I used this yesterday and saved a TON. If you're heading there today, make sure to take this coupon. It's good for today, March 10th only!
Also, make sure to do a rough adding up of your order before you check out. Iif you are at $58, for example, it's worth your while to add $2 in items to your order so that you get $20 off instead of $10!