So wait, you have money for a new fish, but not a $3 thing of dechlorinator? I'm confused. Avoid getting any other fish (snails, shrimp, etc) until you are sure you will have dechlorinator on a regular basis. With a tank that size you need to do 2 water changes a week, with one being 100%, you shouldn't have any algae problems if you are doing the proper water changes.
Plus, if you were to get another fish (snail, shrimp, etc) you would have to actually increase your water changes, not do less. Unless you have a NPT, adding more fish means more work, not less.