Hi - I went through a phase of buying EVERYTHING organic, and if they weren't organic then they had
to be sold at Whole Foods (crazy, I know!) So I used to buy Tom's of Maine. They weren't cheap, at about £4 a bottle. Then one day I got fed up because I was wasting so much money so instead of going to Whole Foods or the usual health food shops, I spent a little longer in the aisle in a supermarket and browsed a few mouthwashes, and found a few which were alcohol-free.
I tried one for 79p and have been using it ever since. Im guessing you're from the US, so the British shop name "Wilkinsons" won't ring a bell with you.
Anywhoo, the moral of the story is, there are a lot of brands which now do alcohol-free mouthwashes, so dont feel the need to have to pay a lot of money by specifically getting a brand name. Branded items are usually more expensive because they advertise their products a lot (on the TV, magazines, etc.) so they have to bump up the price of the item so that it covers advertising and marketing costs. Listerine, Colgate, and Oral B are some brands which are sold in the UK and they do alcohol-free ranges.
I hope this has been of help in some way