CardCastle now uses TCGPlayer Market Price for our card prices.
TCGPlayer Market Price shows a good idea of the current 'true value' of a card by drawing from the thousands of transactions each day from just as many individual sellers. This finds a good average and gives a solid representation of the card's value as decided by what value has been bought and sold. We update prices twice a day from a third party provider.
Click here if you would like to learn more about the TCGPlayer Market Price.
NOTE: Cards from some supplementary products (eg. Commander 2017) are missing. We are aware of this issue and are working to solve it as soon as possible.