Ray Barkalow carries KelpMax. He is a member here and has helped so many of us when we were first starting out with orchids.
KelpMax Kelp Concentrate - Quart Bottle $25.00 Growth Stimulants First Rays LLC
$25 may seem expensive but it will last a long time. Many have suggested keeping it refrigerated to increase the shelf life. I've been using it for about 6 months and have been very surprised at the robust root growth I've seen. Not only are there a lot of new roots growing, but the new roots are huge! I use it when repotting to sort of help things along.
As for buying orchids from BB stores....to each his own. They are good for novice growers to learn on. I have gifted all the ones I had to friends.