You will want to avoid surfactants. How big was the $40 bottle at Ace? I got my ammonia at Ace, and it was just a standard size cleanser bottle for less than $5. You could call and ask if they have a smaller size than the one you saw at your store.
There are other ways to start a fishless cycle. I know a lot of people place a piece of shrimp in the tank and use that as a source of ammonia. You could stick it in some pantyhose and float it in the tank in order to avoid gross particles of decayed shrimp floating around your tank.
Some people also use fish food as a source of ammonia, but I think the shrimp method is generally preferred because the food is dirtier (especially if you keep the shrimp in pantyhose). It's hard to control the amount of ammonia you're adding with both of these methods, but many people do prefer them because they seem more natural than adding pure chemical to the tank, and if you can't find pure ammonia anywhere, these are definite options.