I own about 260 games on steam. a few i got from other sites/stores.

Steam deck purchases are included in this number i assume? I've bought two.

I've spent a total of $191.04 on Steam. First purchase was in April 2016, so we are at almost exactly 9 years. That is an average of $21.23 per year. My profile says I own 65 games, so that is an average of just $2.94 per game. That is heavily pulled down by the bundles. Less than $5 for 8 Half-Life games, less than $10 for 12 Command & Conquer games, and less than $10 for 4 Splinter Cell games. The most I have spent on a single game was $19.99 for Rocket League and $19.79 for Borderlands 3. Most on a single purchase was $27.47 for Dishonored GOTY, Borderlands GOTY, and Borderlands 2 GOTY.

Looking through my whole list, games are just stupid cheap if you wait for sales. Leaving out the bundles I mentioned above, the other cheap highlights are:
Portal 2 for $1.49
Crazy Taxi, Jet Set Radio, Deus Ex GOTY, Civ 3, and Psychonauts all for about $6 total
Mass Effect for $4.99
All 4 Batman Arkham games for $19.98
Witcher 1 and 2 for less than $5
Overlord 1, 2, and Raising Hell for less than $5
Hitman GO for $1.59
Homefront: The Revolution for $2.99 (Timesplitters 2 is hidden inside this game)

Out of my 345 Steam games, it turns out I did not buy any through the platform itself.

Ah yeah, now I remember.

I added 5eur to my Steam Wallet to unlock some profile features and bought a cheap title. I still have approximately 4eur remaining in my wallet.

Stupid profile, made me spend 5eur!!!