Game and gift cards: region and value come first.
Face value, sale currency and account region are different things. Make sure the card fits your account.
Face value and checkout price are different amounts.
A HK$40 card describes its face value; a US$5.74 price describes the payment. They are different currencies, not two US-dollar denominations.
The same brand can issue cards for different countries. Match currency, card type and account region. Ask the seller if the title and detail page disagree.
A code, or a manual top-up?
Automatic code delivery, manual top-ups and email notices are separate steps. Find out where delivery appears, the processing time and how to check an order if email does not arrive.
Gift cards and finished game accounts are different products too. Steam has separate terms for account transfers and product keys; a legitimate gift card does not establish that accounts can be freely transferred. Treat unclear sources and unusual discounts cautiously.
If it fails, where does the refund go?
Undelivered, delivered and redeemed orders may have different support terms. For a wrong region, wrong value or already-redeemed error, keep the order number and a redacted screenshot. Do not post the complete code in a group.
Some sellers refund only to store credit. That is not an original-payment refund and may not be withdrawable. Check the order before paying twice because an email is late.
Official references
Rules can change. Use the terms for your chosen product and provider.