PSA is a card grading company located in America that grades cards based on varying factors. Cards can receive a grade of 1-10.
Grading takes into account the following information.
Card centering, scratches, creases and edge wear to name a few.
These can be minute but can effect the outcome drastically.
The link below will take you to the PSA website.
For convenience and cost effectiveness this method can be great.
We will only suggest reputable services.