Target language: How much is it? It's (5) (Yuan).
Time: About an hour
Age: 5/6/7 (depending on student ability)
Level: Beginner
Suggested knowledge:

1. Do you have a (strawberry)? Yes, I do. / No, I Don't.
2. Noun groups. I.e. food, toys, clothes etc for use in the trading game.

Materials Required:

1. Flashcards of the noun group you wish to use.
2. Currency (I used 5 and 10 Yuan (photocopied) (China) notes). 3 or 4 notes per student
3. Photocopies of noun groups for use in the trading game. Each flashcard should have a price on it. 3 per student.
4. Optional: A picture list of 3 items that the students must collect. 1 per student.

Introduction: Introduce the answer form using a student and an item with a price attached to it. Be sure to point to the price as you ask the question.
Practice: Use varies fun drills. Get ideas from Simply ESL's ideas section. Use noun flashcards with prices on them.
Application: Play a fun follow-up game. Stations, duck, duck, goose (I like this one) or any other game (look at Simply ESL's idea section for inspiration.)

Introduction: Introduce the question form in the same way that you did the answer form above.
Practice: Again, drill the language in a fun way. A game of "What is it?" can work well here.
Application: This is not necessary, as the next activity will be a trading game. Use this only if you have time and want to give your students a little extra speaking practice. That said, play a fun game. X's and O's or target throwing can work well here. Check out Simply ESL's idea section to find an activity that's right for your class.

Trading game
This is what the lesson has been progressing towards. Give each student:

1. 2 or 3 items for them to trade.
2. 3 or 4 currency notes.
3. For an advanced version of the game, give them an item list (3 or so items). The student has to collect, by trading, all the items on their list. The first student to do so is the winner.
4. Another advanced variation is to use the "Do you have a (noun)?" question form.

Demonstrate, with a student or your TA, in front of the class:
S1 "How much is it?"
S2 "It's (5) (Yuan)."
S1 Gives the item to S2. "Here you are."
S2 Gives the money to S1. "Thank you."

For the advanced game (the game I used in my class), just add the "Do you have a ___?" question form:
S1 "Do you have a (strawberry)?"
S2 "Yes, I do."
S1 "How much is it?"
S2 "It's (5) (Yuan)."
S1 Gives the item to S2. "Here you are."
S2 Gives the money to S1. "Thank you."

Demonstrate the negative form (No, I don't.) by moving onto another student and asking the question again.

My students really enjoyed this game; I hope yours do, too.