On the sets main page, after you select it from the search menu, there is a "Collection Summary" box to the right hand side. If you click there and go down to "Cards" you will see an option to "Add/Update." Click there and where it says "Choose an Action" with a drop down menu, you can select the option to "Add all cards in this set to your collection"
I'll never quit collecting entirely, but I am downsizing. Check out my COMC store and help me thin out what I don't want so I can buy cards that I do want. See something you like? Send me a message on here, and we can knock the price down quite a bit. I'll even take a bit of a loss if it means getting you a card you really want.