$1.06 in PLA. $1.33 in PETG. $2.13 in TPU. All three for the same case, around 25 cm³ of plastic and 31 g, on a machine drawing 100 W.
This is one of the few printed objects where the right answer costs twice the cheap answer, and the price is not the reason to choose.
Why the TPU one costs double
Three inputs move at once, and none of them is the geometry.
- Filament price. TPU 95A sits at $25 to $45 a kilogram against PLA's $15 to $28 — $1.09 of plastic against $0.68 for an identical part.
- Speed. Flexible filament is printed slowly so the extruder does not buckle it, so the same case occupies the machine for two and a half hours rather than one. Machine time rises from $0.31 to $0.75.
- Failure rate. TPU is a difficulty-3 material with a narrow window. The figures above assume 12% scrap against PLA's 5%, which adds $0.26 by itself.
But the PLA one is the wrong object
PLA's heat deflection band is 52 to 60 °C. A parked car in summer reaches exactly that, and a phone case is the single most reliable way to leave a printed part on a dashboard. PLA is also brittle: the whole job of a case is to survive a drop, and PLA's response to impact is to crack rather than to absorb.
TPU 95A takes the drop, tolerates the heat and grips the phone. PETG at $0.74 of filament is the reasonable middle if you want a rigid case — tougher than PLA, good under UV, and only 27 cents dearer than PLA all in.
Where the money actually goes
Not into the plastic. A case that fits badly is worth nothing, and getting the cutouts right for a specific handset usually takes two or three attempts.
At $2.13 an attempt, three tries in TPU still costs less than a bought case — which is the honest economic argument for printing one, and it is an argument about iteration rather than about material cost.
Change material, spool price and print time in the print cost calculator, or compare the candidates on the TPU 95A and PETG pages.