Questions about example sentences with, and the definition and usage of "In"

A: "Whose" is pronounced exactly like "who's".

You can listen to the pronunciation of "whose" on the Oxford Learner's Dictionary.
https://www.oxfordlearnersdictionaries.com/us/definition/english/whose?q=whose

A: It would sound like a simple S

A: I came across $50 in my jacket pocket before putting it in the washing machine.

I came across $50 in one of my jacket pockets before putting it in the washing machine.

A: Spend over $100 in the shop and earn a chance in our prize drawing.