These sites all suffer from the same defect, amazon pa-api pricing is NOT consistent in any region with the carted values an end user will be shown. This is a well known thing if you have worked with that api before and you are essentially just dropping the authors 24 hr amz cookie for them to earn off all other sales. Not to say thats bad, but the value add from a price comparison site like this is minimal to the end user as you will very likely not get that shown price.