I haven't used it in a long time and don't remember the exact prices, but if you would like a good idea ask the pool store the price for a case of sanitizer and a case of shock. Get ready for your jaw to drop.

I stayed on it though because of the no chlorine! sales pitch. I thought I didn't like chlorine either, because of public pools. Turns out you don't have any of those problems when you maintain your own pool correctly.

I switched when my pool always had problems and then turned in to a deep green swamp and the dealer just kept having me pump tons of money into the pool. I switched to chlorine using really bad instructions on HTH's website (long since removed), it took about 5 days but everything was great... not one big problem since.

FYI - As far as I know a true chlorine alergy is VERY rare. You would also have an immune system reaction to drinking or bathing in tap water.
A more common reaction would be general chemical sensativity, if the reaction has only occured in commerical pools there is a good chance you would be just fine in a decently maintained chlorinated private pool.