1, 5 bottles of beer (10 yuan), 5 empty bottles and 5 caps;

2. 3 bottles of beer, 4 empty bottles and 4 caps;

3. 3 bottles of beer, 3 empty bottles and 3 caps;

4. 1 bottle of beer, 2 empty bottles and 4 caps;

5. 2 bottles of beer, 2 empty bottles and 2 caps;

6. Beer 1 bottle, empty bottle 1, and 3 caps; (Borrow 1 empty bottle)

7. Beer 1 bottle, empty bottle 1, and 4 caps;

8. Beer 1 bottle, 2 empty bottles and bottle caps 1 bottle;

9. Beer 1 bottle, empty bottle 1, and 2 caps; (Borrow 2 bottle caps)

10, beer 1 bottle, 2 empty bottles and bottle caps 1 bottle;

1 1, 1 bottle of beer, 1 empty bottles and 2 caps, and just returned the borrowed 1 empty bottles and 2 caps.

Total: 20 bottles of beer.