local store = require("store")
    local listOfProducts = {
       "com.yourcompany.app.productID",
    }
    ----------------------------------
    -- In-App area
    ----------------------------------
    local validProducts, invalidProducts = {}, {}

    function unpackValidProducts()
        print ("Loading product list")
        if not validProducts then
            native.showAlert( "In-App features not available", "initStore() failed", { "OK" } )
        else
            for i=1, #invalidProducts do
                native.showAlert( "Item " .. invalidProducts[i] .. " is invalid.",{ "OK" } )
            end

        end
    end

    function loadProductsCallback( event )
        validProducts = event.products
        invalidProducts = event.invalidProducts
        unpackValidProducts ()

        end

        function savePurchase(product)
                --function on what should be save when user buy a product
        end

        function transactionCallback( event )
        if event.transaction.state == "purchased" then
           savePurchase("product") --you should enter here the product being purchased
        elseif event.transcation.state == "restored" then
           savePurchase("product") --you should enter here the product being purchased
        elseif event.transaction.state == "cancelled" then
        elseif event.transaction.state == "failed" then
            infoString = "Transaction failed, type: ", event.transaction.errorType, event.transaction.errorString
            local alert = native.showAlert("Failed ", infoString,{ "OK" })
        else
            infoString = "Unknown event"
            local alert = native.showAlert("Unknown ", infoString,{ "OK" })
        end
        store.finishTransaction( event.transaction )
        end

        function setupMyStore (event)
                store.loadProducts( listOfProducts, loadProductsCallback )
        end


  local onbuyButTouch = function(event)
          if event.phase=="ended" then
            local buyThis = function ( product )
               if store.canMakePurchases then
                  store.purchase( {product} )
               else
                  native.showAlert("Store purchases are not available, please try again later",  { "OK" } )
               end
            end
            -- Enter your product id here

store.init(transactionCallback)
   timer.performWithDelay (1000, setupMyStore)
            buyThis ("com.youcompany.app.productID")
          end
       end
       buyBut = ui.newButton{
           defaultSrc="p1_buyBut.png",
           defaultX = 272,
           defaultY = 68,
           overSrc="p1_buyBut.png",
           overX = 272,
           overY = 68,
           onRelease=onbuyButTouch,
           id="buyButButton"
       }