I make my own "home brew" deer repellent by beating 3 eggs, adding cheap garlic powder, about 1/3 bottle of hot sauce and then pour the mixture into one of my old one gallon Deer Fence containers. Then I fill the jug with water and sit it in the sun to "ripen" till the eggs are putrid. If you are just wanting to spray hot pepper, you could dilute just the hot sauce in a spray bottle. It would be more cost effective that flakes or crushed red peppers. I don't measure the hot sauce that I add....it depends on the strength of what's on sale....if you would be uncomfortable with the hotness, so will the deer.
If you are trying to save tiny seedlings, you can find a product called "Repels-All Granules" at Lowe's and other big box stores. It's an organic that you just sprinkle around and it works pretty good. And it's less offensive to the neighbors!
