You may want to put the minimum download price to $3.50. I accidentally paid for this twice in order to get the full version because there are two tiers for some reason.
I apologize for the inconvenience, It might confuse you but actually the $2 is just a suggestion for donation without getting anything, only $3.5 can get the asset because it has reach the minimum price to get a paid asset. Therefore because of this misunderatanding, I will change the donate suggestion to $3.5 to avoid double payment. Thank you for bringing this up!