Do you have any ideas or recipes for affordable, high value treats?

First, you have to determine what your dog deems as high value, which varies from dog to dog.

I've had good luck with string cheese, dehydrated chicken breast or chicken livers, beef liver.
I've also cooked a cheap roast and diced it up and used that.

I don't have any recipes, I usually use the treats we offer or a freeze-dried version of my dogs' raw food, or one of the options I listed above. I use different treats for different situations. If I’m going to a new environment with a puppy I might use a VERY high-value reward to help stack the deck in my favor for keeping the pup’s interest and focus on me.