I saw something really neat that I want to make when I have a little horse farm again (I'm currently boarding my horse). You can buy those metal carports and turn it into a four horse stall barn, make it look neat by walling up the sides with wood from the inside and painting the roof red or whatever color you like, for around $5,000 roughly. They turn out looking pretty nice too. If you just have three horses, you could turn the fourth stall into a tack and feed room as well. I saw this at Lander University's barn. I thought it was very creative!
I would like to look into that :) What brand/size car garage are you talking about?