Even with a place to stay horses get expensive. Pretty much all horses need an extra mix for vitamins. Additionally you will need to get a farrier every six weeks or so, dentist yearly, have to buy rugs and tack, vet care. Not to mention your horse will grow so its not just one rug you'll need to buy, but you'll have to keep getting more as they get bigger. Youngsters often have a way of hurting themselves and horses can be very expensive to be treated. The costs of transport even, going out there everyday in rain or shine to care for your horse, it really adds up. Its not just the food and agistment costs that are involved with a horse.
Additionally, getting a yearling you won't be able to do much with it for a while. You'll still have to go out and feed and rug and check it everyday, but for two years you'll just be going over ground handling pretty much. Then you'll spend a few months of regular dedicated work to start it, and then usually people put them out for another 6 months or so. Even with very experienced help chances are you won't be able to just relax, have fun and ride for probably 4 years at least. And if you can't keep it you probably won't get close to the amount of money you put in.
I mean I would get a broke horse. Its not a huge process so its not like its going to be life changing for you to break it yourself, its not inspirational or particularly fun. Its just lots of repetitive, careful work that can be quite dangerous if you don't know how to act in a certain situation. Once you get on its not like you have a fun horse, its months or years of just putting experience on the horse, day in and day out. But if you really want an unbroken horse I would go for a three or four year old. At least you can start working on it now rather than having it sit in the paddock for years. It's just hard to do things with young horses because most of them are, mentally, like children. Limited attention span, over sensitive and unpredictable.
Make sure you know what you really want. A lot of people have a romanticised view of horses - I know I do, I always think it is so great and then I get a horse, and I like it and care for it, but you forget how much mundane work there is. And it gets old after a while, especially in winter where you just want to have dinner but you have to go out there in the dark to feed and rug your horse, and you just want to sleep in on a Sunday but you have to go do your horse. A young horse is even harder, and is going to be harder to sell if you decide you don't want it later on.
Why don't you lease a horse for a little while, just to make sure it is what you want?