Bitcoin payment timing out - is this normal?
Yeah, that 15-minute window is pretty standard across most shops—it's basically how long they'll hold the exchange rate before it refreshes. The volatility on BTC can swing a few percent in that time, so locking it in is their way of protecting both sides. If you're late, you'll often see the price jump, and then you gotta start over with a new quote. It's annoying but fair.
Your hot wallet tip is spot on. I do the same—keep a little BTC in Coinbase Wallet (or any non-custodial wallet) ready to go. Sending from there takes maybe a minute or two, max. But here's the fee hack: always check the mempool before you push the transaction. If fees are high, you might need to bump the sat/vB to get confirmed within that 15-minute lock. Some vendors won't credit the payment until it gets one confirmation, and a stuck transaction can cause a timeout even if you sent it on time. On that note, using a SegWit address for your wallet keeps fees lower, and the transaction size smaller—faster confirmations.
And yeah, never try to buy fresh BTC and pay in the same session. By the time the exchange clears your deposit and you can withdraw, your rate lock has already expired. Plus, buying on an exchange like Coinbase can take 5-10 minutes just for the ACH to settle, and then you're racing the clock. Just keep a small stash in your hot wallet for when you need it. On the pricing side, expect the amount to be quoted in fiat equivalent, then converted to BTC at the locked rate. Some vendors include the network fee in that price; others don't and tack it on at checkout—that's a hidden fee to watch for. Always check their FAQ or ask support if the quoted BTC amount includes miner costs.
Escrow safety: I know this isn't directly about timing out, but it's worth mentioning. Only use a vendor that offers escrow—either through a market or a trusted third party. Never send BTC directly to a personal wallet unless you fully trust them. Even with the 15-minute lock, some scammers will take your payment and ghost, then claim it "timed out" to get you to resend. Escrow protects you from that. For the payment itself, double-check the receiving address matches what's on the vendor's site—clipboard malware is real. And if they give you a new address each time (which is good practice), make sure it's from the current session only.