You’d be surprised how cheap it is to build it yourself. I built 2 windows out of scrap wood/steel and about $10 worth of plastic. I recycled a steel door a friend was throwing away. Except for the cement and roof trusses I paid for it as I went along.
A former owner put a 10’x40’ travel trailer next to the house and built a structure around it with a passageway to the house proper. So I’d have to have the structure demolished and the trailer hauled away. Since the ground slopes, it would need to be leveled. Then there’s the concrete, and the new structure would have to be incorporated into the structure of the house. I asked about five years ago, and was told it would cost $10,000 to $15,000.
I’d like to widen the driveway by ten feet. That will cost less than a garage, and get the Jeep off of the street.
$10K for the garage sounds right if you did it yourself. Driveways aren’t cheap but you could pour it yourself pretty easy. Pretend it’s an airplane and throw money at it.
Hey, Johnny, you still have nice firearms (which are much cooler than vehicles)! Unless you sold them, that is.
Only, I’m non-violent! 
Actually, I did sell the 1927 Winchester, and the 1967 Canadian Commemorative Winchester. Next on the block will be my unfired Shiloh Sharps 1873 #3 Sporter. And I really need to sell some of my 16mm cameras.
After our string of hit-and-runs (three in four years), when we went looking for our next house, garage or able to build a garage was top of our priority list. We have a garage now, and I won’t park the car on the street even for half an hour. I didn’t even realize how much worrying about the cars was weighing on my mind until the snowstorms started with our cars safely tucked away in the garage, and I realized I didn’t have to worry about assholes running into them. What a relief!
Just to pretty-much finish this up: The Jeep is currently in the shop. I took it in a week ago Friday. Damage was a little over $2,300, and my deductible is $300. As long as it’s in, I’m having two other things taken care of. The gas pistons that hold up the rear hatch are weak, so I’m having them replaced. (I’d so it myself, but last time I got a pair of them they had the wrong ends.) Also, someone egged the Jeep and I didn’t get it off in time and it etched into the paint. (I’ve really got to wax that thing once in a while.) So I’m having a door repainted. I don’t know when it will be ready to pick up, but I assume it will be done this coming week. I’ll find out how much it will cost to have it detailed, which will get me that nice coat of paste wax. I thought about getting a cover for it, but then I might not notice if someone hits it again.