We use USPS Media Mail shipping for orders of up to 25 records:

1-3 Records $6
4 Records $6.50
5 Records $7
6 Records $7.50
7 Records $8
8 Records $8.50
9 Records $9
10 Records $9.50
11 Records $10
12 Records $10.50
13 Records $11
14 Records $11.50
15 Records $12
16 Records $12.50
17 Records $13
18 Records $13.50
19 Records $14
20 Records $14.50
21 Records $15
22 Records $15.50
23 Records $16
24 Records $16.50
25 Records $17