According to Walmart, for online payment by check card, the payment amount is authorized and held by your financial institution at the time you place your order. Your account is actually charged when your order ships.
For in-store payment, if you use a check card, your account will be billed immediately. If you pay by check, checks will be cashed soon after tender.
Using electronic checks allow customers to issue payment a day or so before the funds come into their account to cover the check, otherwise known as "floating" a check.
Other sources suggest that if you write a check to Walmart for items purchased it will process that night by eft (electronic funds transfer). Which means they are instantly debited from your account like using a debit card.
Walmart.com accepts the following payment methods:
- Credit cards, including American Express, Discover, MasterCard, and Visa
- Walmart Credit Card and Walmart MasterCard
- ATM / Debit / Check Cards, including Walmart MoneyCard
- Walmart Gift Cards and eGift Cards
- Pay with Cash (cash, checks, EBT, and money order can also be used with this method)
Check out Federal Trade Commission's shopping tips that can help you get the most for your money.