How do I increase the amount of points available when someone buys a Dev Product?

I'm trying to make a points distributor system and it seems to be working fine, but I can't figure out how to increase the amount of points on the server. This is what I have:

local id=19644738
function click()
	game:GetService("MarketplaceService"):PromptProductPurchase(script.Parent.Parent.Parent.Parent, id)
end
script.Parent.MouseButton1Down:connect(click)

Please copy this code block and add onto it when you answer.