For arguments sake; cause I do like to argue both sides;
You would probably spend between $1,000-4,000 per mowing cycle, or I would think a min of $2,000-8,000 per year, with just two mowing. That's a lot of money, but at the same time; let's look at a TYM 574, at $35,000 (or so), a 8 foot bush hog at $4500 (or so); fuel for 16 hours per mowing cycle; you Might be able to hire it mowed for between 5-20 years, before you reach break even point on the purchase.
Now, the other side; I would look at your budget, and if you can swing it, get the tractor and bush hog. I would expect, for $650/month, you can build a heck of a brand new cab tractor, with large mower, and loader. Now, that's $7800 per year, plus fuel, and you are within the range of what you might be paying to someone else to do it. You mentioned hunting, so a couple 2 acre food plots; possible fence work; ect, and you have something to show for your money. You can decide when to mow, what areas you want to mow, ect, on your schedule.
Also, maybe you can find a guy to mow for $50/hr now; don't think that rate isn't going to be x3 that in 5 years. Heck, right now, I would expect to pay atleast $80/hr, if not $120/hr.