Google has some words that it will use variations for. In a search for Supplies Store you will notice that the word Supply is also in the bold results. It is a great shortcut if you can dominate a phrase using supply and allow it to work for both as google seems to allow.

A search for product store does the same. It uses the plural along with the singular. This is not always the case in for some words.

When doing a search for beauty product supply store you also see the variations in the results.

So then you tend to wonder if one is more important than the other. From experience in only one of the keywords you are asking about I can tell you that it doesn't matter. It is the word supply verses supplies. You can use the singular and it will count the same as the plural. On the other terms I cannot say for sure.