Crypto prices move, so checkout works in two stages.
Before you continue: an estimate
The amount under Estimated total in is a guide. It refreshes every 15 seconds, and Refresh price updates it now. It can change between refreshes.
After you continue: a locked price
When you choose Continue with your asset, the exact amount is locked for a few minutes. Time left counts down on the payment page. Send the exact amount shown before it reaches zero.
If the timer runs out
The page shows Payment expired. Nothing is taken from you. Start a new payment from the merchant's link and you will get a fresh price.
If you already sent money just before it ended, keep the page open and wait. If it still shows Payment expired or Payment failed, see the article on a failed payment.
If the price cannot be locked
You may see Unable to lock the price, This payment method cannot be priced right now, or We couldn't calculate this price. Check your connection and refresh the page, or pick another asset or network.