Press your lips together to stop the air, then release. No vocal cord vibration.

Americans pronounce purposes as PUR-puh-suhz (/ˈpɜrpəsəz/). Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "Bamboo grows very quickly and is used for many purposes".
Record yourself saying "purposes" and play it back. The mic stays on your device — nothing's uploaded.
3 syllables, 7 sounds. Tap a syllable to jump to its row, then explore each sound's mouth shape and how it's made.
The textbook way isn't wrong — it's just not how anyone actually says it.
Stress falls on the first syllable, not the others. Stretch PUR — keep everything else short and quick.
Don't pronounce the first syllable too fully. The unstressed syllable reduces to a schwa — the lazy "uh" sound — in casual speech.
Americans use a relaxed retroflex R — the tongue curls back rather than rolling. The R is one continuous sound with the vowel before it, not two separate sounds.