I was having the same problem. But I just found a solution to it! If you look at your right toolbar on your Itunes page that says Music Movies Tv Shows etc... then go down and double-click on Itunes Store and then a new page will pop up and it's big enough for you to click buy on which song you want... HOPE THIS HELPS!! IT HELPED ME!
FOUND ANOTHER SOLUTION. IF YOU HAVE A SCROLL ON YOUR MOUSE CLICK THE SCROLL ONCE THEN MOVE YOUR MOUSE LEFT TO RIGHT this way you don't have to open another window and save on your ram
The CTRL+Scroll trick works, but I'd really like my scrollbar back. The computer I am using iTunes on has a newer version than they even have on their feedback page. It must be an issue with that version specifically (9.0.3.15). It only started for me in the past week or two... I pulled my hair out before finding this thread - just trying to scroll at
all.
Since there is no iTunes correction yet, I bet there won't be one. Our best bet like others have posted is to dbl click on iTunes Store to open a full screen session or go to Edit/Preferences/Store & click on Use Full Window for iTunes store. I checked with my husband to see if he was having this issue and he wasn't because his monitor is wide enough to show everything.
I feel obliged to respond. This is a permanent fix to the problem. Just open up iTunes, go to: "Edit" --> "Preferences" --> "Store" --> "Use full window for iTunes Store"' You can now go to the iTunes store without any problems, and just click on the "X" on the LEFT hand corner of your screen, which will take you back to your Library.
Hope I was of some help to everyone, this problem is totally annoying me as well.
My scroll bar just reappeared a little while ago. Not sure if iTunes finally listened to us and fixed it or what but it is definately there at this time. I've even closed iTunes and reopened it to make sure.