Knowing we all want and need squad points I thought this would work and did. This is a one time use but you can purchase the first 6 characters I believe for 3 squad points. Now for every level you will get so many which will easily make up for what you paid to buy the characters!
I got a total of 94 squad points just by doing these steps.

Steps:
1. buy all characters that are 3 squad points
2. rank them all up to about level 4-10
3. Done you will receive triple the amount you paid for the classes
Enjoy