All games are under 5€ games. Bought like 10 of them and all were under 5€ games.
To elaborate, buying from any random Steam key seller is always a bad idea. The way these people make money is that they obtain keys at low prices through various means. These means can vary depending on the seller. Some use keys they obtain for free or from bundles such as GOG or Humble Bundle-- these are usually the better (yet, still bad for the customer) dealers. Then there are also the gray-black market dealers, which use keys stolen from some developer or publisher database to make people believe they are getting a legitimate copy. The latter most likely results in the keys being revoked by Steam (yes, this is entirely possible but most people don't know it). Furthermore, while most sellers say you can get AAA games from their random keys, this is pretty much always a lie. All you will ever find in these keys are low quality or low cost games. I can guarantee you will never get a copy of GTA V or PUBG.
Also, even though some sellers may claim that they do not know what keys belong to what games, that is a lie meant only to take "the blame" off of the seller. They know exactly what they are selling and they know that you are not going to get anything of value. Stay away from these kinds of offers, both here and in sites like G2A.