The deductible is how much you have to pay on your own before the insurance kicks in. Of course, it's almost never as simple as that.
Usually, the plan with the higher deductible is somewhat less expensive, because the insurance company expects to pay out somewhat less, on average.
One thing that may help is to find out if it is some sort of group plan or an individual plan. If it is a group plan, the rates are probably somewhat lower, and it may well be a good deal. Individuals represent a greater risk for the insurance companies, so they charge more for them (it might be a good deal even if it's an individual plan).
One way to think about the whole thing is this: It is very unlikely that anything super outrageously expensive will happen to you. But, if it does, and IF your insurance will cover it (a big if), then you get to walk through the other side relatively unscathed financially. If you don't have insurance, and something awful happens, you've got a couple of options. One is to beg and plead for free/low cost care, which is generally pretty hard to come by. Another is to saddle yourself with the debts (in a hospital, one tylenol pill costs about $20-$30!). A third is to declare bankruptcy, which will only set you back seven years from being able to pay for anything except with cash. So even though it's expensive, it's a good idea to pay for it if it is at all possible.
BTW, going into teaching means you'll never have to worry about insurance again. People can grumble all they want about teacher's unions, but without them we (in the teaching profession) would be totally screwed. But that's another topic entirely.
Good luck with your endeavors!