On Receiver, insert the name of the SHOP OWNER name. (In the Random Game's case it'd be Xyphien)
On the amount, insert the amount of GH$ the shop item is being sold for.
On the description, put the name of the item you're purchasing (in your case, "Random Game")
Click pay for tax.
There is a system tax on all bank transfers, the amount depends on how much you're sending, I think. If you tick pay for tax, the fee is added to your total (so it's deducted from your GH$); if you don't check it it's deducted from the total sent (so in essence you're paying less than the asking price).