it depends how many stalls you want and how "fashionable" you want them, but when you build them you also need to think of the basic essentials like buckets, hay nets, shavings and all those type of things
The cost may vary depending on how many stalls you want. Do remember that you will have to pay for 1. The arena 2. Fencing 3. Barn supplies such as: rakes, cross ties, shovels , wheelbarrow/ muck bucket, water troughs, hay feeders, and mounting block 4. Alfalfa/ hay 5. Shavings (if you use them). I hope that helped. Just know what your getting into I should know I'm doing the same thing!