I love this idea. Would be really a cute set up for a family photo too.. Parents on the outside kid on the inside, vice versa..
You can get the vases at Dollar Tree for $1 each. 3 bags of the rocks at $1 each, and the floating candles in a 6 pack for $2.99 at Hob Lob. With a super gorgeous orchid as the flower, in the colors of the wedding, you've got yourself a very pretty, and very thrifty centerpiece!