The amount of money that is limited per money order at Walmart is $1,000.00
That means that you can purchase one money order for up to $1,000.000 plus the money order fee which is $0.70 and then if you need more money than that on a money order you have to purchase a second money order and pay the money order fee again.
USPS limits the amount of a money order to $1,000.00 as well plus they charge $1.20 per money order at my local USPS.
So both USPS and Walmart limits the money orders to $1,000.00 per money order.