Lift your bottom lip to touch the very bottom of your top front teeth. Blow air through this contact point without voicing.

Americans pronounce fifty as FIHF-tee (/ˈfɪfti/). Stress falls on the first syllable — keep everything else short and quick. You'll hear it in sentences like "I bought it on sale for fifty dollars" or "My grandfather is over fifty years old" — more examples below.
Record yourself saying "fifty" and play it back. The mic stays on your device — nothing's uploaded.
2 syllables, 5 sounds. Tap a syllable to jump to its row, then explore each sound's mouth shape and how it's made.
Lift your bottom lip to touch the very bottom of your top front teeth. Blow air through this contact point without voicing.

Drop your jaw slightly with relaxed lips. Touch the tongue tip behind the bottom front teeth and arch the top-front toward the roof.

Lift your bottom lip to touch the very bottom of your top front teeth. Blow air through this contact point without voicing.

Click any sentence to see the full breakdown — every link, every reduction, every flap-T.
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 FIHF — keep everything else short and quick.