The mod changes the price of the “Untitled 18 – Brancesi, 2021” painting from €$⁠8⁠000 to €$200000.

 — Cyberpunk 2077
 — mods: TweakXL 1.5.2+ and its dependencies

 — Check/install/update requirements
 — Extract the archive into the game’s main directory

[€$?]: Why this number / what would be the real price?
As the in-game description states the Untitled 18 is “an extremely valuable painting”, so let’s look at the most valuable paintings already sold in the real world. I believe the best example to be “No. 5, 1948” by Jackson Pollock, which resembles the Untitled 18 in style, dimensions and naming convention. And it was bought in 2006 by none other than David Martinez himself, for 140 million US dollars. I assumed €$ to USD ratio to be around 1:4 – e.g. hypercars in the game cost about 1:10 real USD amount + they are second-hand + some discount ≈ 1:4 (then $40 for a soda can? Let’s call it a sugar tax, we already have it in Poland :p). So we arrive at 35 million eddies for an extremely valuable painting. But our ownership of it is questionable. Then 1/10 for a black market value? I have no idea, but I assume we could still get a few million. As it would be difficult to sell in the game, I’d like to go back to the beginning. Upon consideration “an extremely valuable painting” doesn’t exactly mean it is anywhere near the top, it could probably be a few million USD as well. Apply the above calculations again and we get €$200000 :) And if you don’t like the price, feel free to modify it in /r6/tweaks/Untitled18PriceFix.yaml

 1] Go to {GameDirectory}/r6/tweaks/ folder
 2] Create a new text file and name it HoweverYouLikeBut.yaml
 3] Open it with Notepad++ or any other notepad
 4] Type or copy and paste the following:
`# I solemnly swear to use my psiberx-given YAML Powers of TWEAK-dimension-manipulation only to spread joy among humans, #
# humanoids, cyberhumans, anthropomorphs, and to provide good quality food to all cats in need, with generosity         #
# that may be bound by limitations solely when serving the plump ones, and this only with their health                  #
# and future wellbeing in mind. Furthermore, I pledge never to employ the knowledge I have acquired herein              #
# to contribute in any measure towards enabling the use of Comic Sans in any game mod nor other digital work.           #

# Change the price of Untitled 18
Price.MQ003_painting.value: 200000`

 5] Save the file. [!] Make sure it is saved in /r6/tweaks/ (can be in subfolder) with a .yaml extension!
 6] Run the game and enjoy!