Renting equipment is a fairly common practice; especially for gear that you'd only use a few times each year. (Or for gear that is very expensive)
Since you mention you'd be using it "quite often", you may as well make the plunge and buy it.
To borrow for free, try these:
1) Have a friend who owns one, and mooch as often as possible. This is great 'til they start to see all the wear & tear being put on it, and they suddenly wise up when they have to buy replacemnt pieces.
2) Check with your local cable company. Arrangements vary wildly from region to region, so this may or may not be available to you. My old cable company (Time Warner, upstate NY) offered year-round classes in video editing, use & care of equipment, access to hard-wired video feed taps (for local events coverage), all kinds of great stuff - all for free - after having completed their free training courses. Ideally, whatever you produced (using their facilities & gear) was to be shown on local cable access programming. So you'd end up with free exposure, as well! You should definitely check with your local cable co.
That's all I got.