You can't budget for what is unknown cause each art piece/project has a specific set of materials per the vision. Thats why artist of my caliber are usually broke consistently for their projects. And nope, the cost of transportation varies based on miles and due to White folks not checking for emerging artists anymore since the Floyd uprisings the Black artist bubble has burst.
These are definitely surprise expenses because you run out a paint and that's why I buy up all art materials as money comes from a sale, because you will never know when you get your next sale again.

But let me break it down further for you....
Also the car metaphor sounds clever until you poke it once.
-A car is a fixed system with known parts.
-An artwork is an evolving organism that mutates mid-process.
-Tires don’t suddenly decide they need gold leaf and 4 yards of raw sienna collage paper.
You start a piece thinking: “acrylic and oil stick.”
Halfway through: “this needs copper leaf, a Xerox transfer, and a whole new panel because the energy is wrong.”
Real variables you aren't considering:
-Vision shifts mid-process
-Materials discontinued or out of stock
-Scale changes because the work demands it
-Shipping and transport fluctuate wildly
-Sales are irregular and seasonal
-This isn’t poor planning, its working in a field where the painting or panel does not exist until you bring it into existence.
The broke artist trope isn’t a joke at all.
We artists aren’t broke because we forgot to open Excel.
We are broke simply because:
-Market validation lags years behind production
-Gatekeepers move goalposts
-Collectors buy trends, not trajectories
-Materials cost upfront; recognition pays later
-You front the cost of culture and society pays you in hindsight, watching you struggle and then you prevail everyone wants to champion you, and then when ya art is too expensive they price shame you for not keeping the art affordable when no one wanted it out the gate.
People love telling artists how to "budget" because it lets folk like yall pretend creativity is a hobby, with receipts instead of labor with risk.
Yall want art to exist.
Y'all claim how Black art is of the culture.
Y'all just don’t want to understand what it costs to make it.
And yet I keep building panels, staining edges, conjuring worlds of Black excellence out of wood and pigment like some stubborn Hoodoo man refusing to clock out. So yes I ask y'all for support, because I'm not doing this art shyt for me, I'm doing it for US.