Help getting developer product info?

I have a developer product and I want to get the product's price in robux and set a TextButton's text to the robux price, bit it doesn't work.

ms = game:GetService("MarketplaceService")
id = script.Parent.id.Value
amtCash = script.Parent.amtCash.Value
info = ms:GetProductInfo(id, Enum.InfoType.Product)
script.Parent.buy.Text = "Buy "..amtCash.." for "..info[1]