I buy it at Lowe's Liquid Fence, Deer & Rabbit Repellant. I buy the concentrate and mix it, but if you don't need a lot of area covered, I'd suggest buying the ready to use because Oh My God it stinks so bad, mixing it is nauseating. It smells like rotten ceasar salad...I can't eat ceasar salad any more *brrfftt*. This stuff works well for me. I spray my hostas and other deer treats every few weeks. If I notice a lot of deer activity around the property (hoofprints, droppings) I drape bird netting over the hosta bed for added protection. So far, using this method, I've done pretty good. Also, when you spray the stuff, spray it on plants AROUND the plants you want to protect so the deer never get their noses actually into the plant you are protecting. I usually squirt a bit along paths, on rocks and logs, etc. It smells very bad while youre applying it and you will get a whiff of it for a few hours, but once it dries you can't smell it.
