For the cans, your options are endless - obviously if you don't want to paint them, you can leave them natural and decorate the tin! But since I had some old paint sitting around the house anyway, I thought I would spruce them up a bit. Peel off the label first of course (sometimes you need a little Goo Be Gone to get off the seal from the label to the can) and then paint! Some were fine with 1 coat, but a few of them needed a touch up with a second coat. Overall, not too time consuming of a task if you do them all at once. Then garnish with ribbons, bows, other flowers - whatever you have! Scrapbook supplies are good for this.
My daughter is going to attach little tags to some of these for gifts - you can write a little 'Thank You' or some corny rhymes "If you were a flower, I'd pick you - thanks so much for all you do!" or whatever you want to go with - attach them to the holder on a cute twine tag or something to match how you decorated it. It's a cute/practical EASY gift for your child to make on their own (or with a little help depending on their age of course).
So don't throw out those old cans - paint them and turn them into something adorable instead. :)