If you wanted to see something like this:
group product price lowest price
television lg $388 $388
television rca $430 $388
television sony $478 $388
microwave amana $138 $138
microwave panasonic $158 $138
microwave ge $169 $138
that CAN AND SHOULD be all done in a SQL query.
And then your PHP code would just pull the data from the records and display it with no futher PHP processing.
If that's what you are after, provide some sample data to work with and I'll show you how.