can you buy royal icing already made ? like you can any other icing ?
No. You can buy it as a powdered mix to which you add water. It runs about $2-2.80/ 1# bag. Most cake deco shops carry it.
Wilton also makes it--a 14 oz. box--for $4.99. I can't say I've ever seen it, but then again, I've never looked for it. If Michael's carries it, it would be OK pricewise if you used a coupon.