When shopping for a flat iron it is important that you first identify your hair type so that you can purchase the best flat iron that would be perfect for it. People do not all have the same hair type and flat irons also differ depending upon the manufacturer as well as the model of the iron that you might be going through. It is therefore recommended that you start looking for websites that provide flat iron reviews so you can go through the recommendations on the best flat iron for your exact hair type.
Do not simply go ahead and purchase the best flat iron based upon its price or its popularity as that is not going to serve your purposes at all. Unless of course the vast majority of people share the same hair types as yourself in which case it may well be a good idea for you to proceed further accordingly. You may therefore want to visit to multiple websites that provide flat iron reviews so you can get an idea on the best flat iron as recommended by different websites.
If you find the vast majority of websites recommending the same hot iron as being the best one then you would have a clear choice to make. Otherwise it would be about identifying the one that is recommended by the vast majority of reviewers online.