Incorrect Numbers?

It's a common bug with packs. Instead of the price of the game itself, if there is a pack which costs cheaper than the game, steam reports the price of the whole pack. In this case: http://store.steampowered.com/sub/92274/

It's a bug that happens when the package / collection is on sale. Or rather if the package is cheaper than the main game at that very moment.

Both of them are $8.99. Meanwhile the package is $5 because it's 90% off right now. Originally $50 which is why you see them being worth 50p.

It will be back to normal when the sale is over. :p Same thing happens with the Deponia games etc.