You can purchase large outside dog kennels/cages for a very reasonable price at your local home improvement store like Menards. They are made from chain link fencing and are very sturdy and easy to put together. Depending on the size you want they can be less than 200.00. You can also find used chain link kennels on places like Craigslist that are in good shape and less money. I sold 2 kennels that way that were in excellent shape thinking I would never get another big dog but then 2 years later--another big dog! Wish I had kept them! I initially set mine up on sidewalk blocks configured in a rectangular shape slightly larger than the kennel to eliminate digging under the kennel. I have since constructed a wooden deck attached to the side of a small garage along with a roof also attached to the garage for the kennel--a lean to shed basically--that protects my dog from the sun, rain and snow.
Walmart has a good selection online...https://www.walmart.com/search/?cat_id=0&query=dog+kennel Your dog should have room to move around, water and food, and shade area. Usually put some pea gravel and some sand area on the bottom. Then you will need a pooper scooper for clean up.
There are lots of dog houses ideas here on Hometalk. They might inspire you or help with your dog cage: https://www.hometalk.com/search/posts?filter=Dog%20Houses
It would have to be large