We're currently experiencing a bug with GMG prices caused by incorrect information in GMG feeds.
There's a multibuy promotion which enables customers to pick up 5 games for £5 / 5€ / $5. The prices in GMG backend are set to 1 so that when the game is added to the basket it appears as only £1 / 1€ / $1 but customers need to add 5 games to the basket in order to checkout.
However, it is impossible to purchase these titles individually at £1 / 1€ / $1 each. Therefore prices in feeds are technically incorrect.
We will try to fix the issue manually and remove incorrect prices from GG.deals. We have also reported the bug to GMG.
If you want to take advantage of multibuy offer, you can do so at this link - https://www.greenmangaming.com/mix-n-match/