If you're not opposed to spending some Farm Cash to get ahead, you'll be happy to know that all Animal Habitat expansions can be purchased outright with Farm Cash. What's more, those expansions currently happen to be on sale. You'll know if you have these sale prices available to you if a pop-up like the one below appears on your farm at login. Your own menu will vary, depending on how many of each Habitat you have on your farm and how many you've already completely upgraded (the 0/1, 0/2 numbers will vary), but the general process works in the same way.
You'll simply be able to look around the window, picking out which expansions you'd like to complete with Farm Cash, with the costs seemingly depending on how many parts you've already placed manually. As you can see, my Horse Paddock is the closet Animal Habitat I have to being completely expanded, so it costs the least amount of money. Formerly, that expansion would cost me 14 Farm Cash, but with this sale, I could save a single Farm Cash.
While that may not seem like a lot, look at some of the other expansions - 75 down to 68 Farm Cash, for instance, on the two Wildlife Habitats. Again, these numbers vary between Habitats, and will likely vary in your own game as well. What stays the same is that you're guaranteed to save at least some Farm Cash if going this route. Is it worth it? That will ultimately be up to you, but I think I'll personally stick with collecting free ingredients the old fashioned way.
Will you expand your Animal Habitats for Farm Cash during this sale period? Sound off in the comments.