Q.Where Can Buy Coleus Canina
it is a cat repellent

Certified GKH Gardening Expert
That is just an old wives tale. There is no proof the plants repel any animal. However, they do have a foul odor, especially when brushing up against the plant.
It is a perennial herb in the mint family. I would check with a local nursery and see if they carry it or know where to get it. I did an online search and came up with some individual sellers which I don't know that I would trust.
https://www.gardeningknowhow.com/ornamental/flowers/scaredy-cat-plant/growing-scaredy-cat-plants.htm