If you want volume one and two it would be better to pay $38 for that SDA bronze upgrade and get those and more than just paying $30 and change for those two volumes only. At least that's how it worked out for me I paid 38 and change for SDA bronze upgrade and got those two volumes plus a bunch of other resources. One of them cool tricks about dynamic pricing that sometimes works out for you but sometimes works out against you. Just a thought 
DAL
