You watched a movie at the cinema last friday
A mercadillo is a street market so you can buy all kinds of things there. So I would say:
At a mercadillo you can buy clothing, Spanish street foods, and meal ingredients such as spices, fruits, and vegetables. A mercadillo refers to a traditional market that is usually held on the weekends that’s in a commonly spotted area with Spanish/ Hispanic/Latin culture.
Hope this helps!
Quisieras que te dijera un "secreto*
it means would you like me to tell you a secret
Espero haberte ayudado (;