The three most common filaments cover three different jobs, and most disappointing prints come from mixing them up.
PLA is the precision material: it prints cleanly, holds detail, and is perfect for prototypes, display parts, and indoor fit checks. Its weaknesses are heat (it softens around 60 degrees) and UV. PETG is the durability material: tougher, more temperature-tolerant, slightly flexible, fine outdoors for a few seasons; the trade is stringier prints and less crisp detail. TPU is the flexible one: gaskets, seals, bumpers, vibration mounts, anything that must bend and return.
Our per-gram pricing is public on the marine page: PLA $0.12, PETG $0.20, TPU $0.25. When a job needs more than these three can give, that's what ASA and the carbon-filled nylons are for.