How to make a dev product that multiplies the current money?

local MPService = game:GetService("MarketplaceService")

MPService.ProcessReceipt = function(purchasInfo)
	local plr = game:GetService("Players"):GetPlayerByUserId(purchasInfo.PlayerId)
	if purchasInfo.ProductId == 989677509 then
		plr.leaderstats.Money.Value = plr.leaderstats.Money.Value * 2
	end
end

this is what I have, but when you buy the product a second time, the money multiplies by 4, 8, 16, and so on. How could you fix this?

Edit: It also seems to be printing a value twice, four times, and eight times, depending on how many times you've bought product

Edit 2: this multiplication issue seems to only persist with a dev product