I have stopped buying so much milk as i used to and instead have been getting 5% happy pills when my kitties are ready to breed because im also lazy to carry them around and too impatient to wait for them to gain that 5%. Altho I haven't done any math on what it costs me to make all my cats happy (when they are ready to breed), but They would eat more milk while gaining love and i would probably end up spending more $ on milk than buying them happy pills. Its just a hassle to buy single pills x10 rather than a pack of 10 and so on
When I do buy milk, i dont put it all out anymore; maybe like 2 cans for the cats at 98%
I try no to give them love pills because I save $ for food but as i mentioned i can be impatient lol so I occasionally buy love for them too
However, I doubt the cost on the things you mentioned would be lowered anytime soon lol. I already suggested an annual food sale but that will never happen
