those are a few known problems, when the sale started, everything that was released was changed to $0,99. this includes the free songs available.

i dont know if it just shows up with a price in the store or that it actually cost that price (will get to this in a sec). but you should be able to get them for free anyway once the sale ends.

as for the wrong price on the offspring song. there are a few songs that say they cost $2 while they should be one. i can understand if you dont want to risk this. and it would be better to wait for someone else to confirm this (on the particular song would be best) but if i remember correctly then it should only take $1 from your account even though it says $2. again, not saying i'm 100% sure about that.
this might also be the case for the free songs, but again. wait till other people verify this as well

as for the freezing. it only appears frozen.
for some reason it doesn't show how much progress it's making when loading new songs after you leave the store, like it does when you start up the game. just leaving it like that for 10 minutes should fix it.