Here are the answers to your questions:
Question 1: Which of these is a kind of shirt?
Answer: la sudadera (The correct answer is "la camisa," but since it's not given, "la sudadera" is the closest option, even though it refers to a sweatshirt.)
Question 2: When would you say "Te queda bien"?
Answer: when your friend looks nice in a new piece of clothing
Question 3: Who might be found selling in a store?
Answer: el dependiente
Question 4: Which would you use for referring to two shirts?
Answer: dos camisetas (if you mean t-shirts) or dos camisas (if you mean dress shirts)
Question 5: Which word means 500?
Answer: quinientas
Question 6: Choose the correct verb: Yo ______ comprar esta chaqueta.
Answer: quiero
Let me know if you need further assistance!