What are best value decorations for coins spent and waiting time?

I don't think I've seen any cost vs time analysis. I just always have something of high value cooking, so when I need it, it'll be ready by then. This link shows the highest cost decorations (and what level/# of stars they will be available) which will get you further in the game than low value decorations. Also look at the seasonal set decorations which may offer something similar or better. https://www.gamersunite.com/scenes/decor-with-500-prestige-flowers