Emilyandlily Store via eBay offers the Godox Speedlite TT560 Flash for $37.97 with free shipping. That's a buck below our April mention and the lowest total price we could find by $2. It's compatible with Canon cameras.
reviews on amazon are very good: http://www.amazon.com/...1&sortBy=byRankDescending
but it depends what do you need it for, major factors for me when I was buying Canon speedlite 430 EX ii were the recycling speed, auto mode and other settings passed from camera to flash + one of the major one that you'll need when going to your children's graduation, churches, whatever is the distance - how far it can strike to reach the object - 430 ex were going by 43 meters, but I couldn't find that info about this flash.