Hi Abdul,
Since a respondent will be assigned only one brand out of total available brands, so you can create a single quota having 500 cells (one cell for each brand). The limit of each cell will be 1 as 1 brand can not be assigned to more than 1 respondent.
Also, in the cell membership method, please select Least fill (percentage) so that the brands can be assigned on the basis of lowest read.
Hope this helps.
Regards,
Rahul Mittal