My local store has albino and green cory cats, ottos, and many tetras for $1.00/ea this week. May want to check your local area. Hope it was ok to mention this.
Quarantine in a tank with no light or very low light. This time of year the sale neons and cardinals are wild caught. They don't know what flake food is. Try a wide variety of foods several times a day for a few days, and keep the tank bottom cleaned. I purchases 40 at the last $1.00 sale and lost one or two.