This is the lesson that saves people the most frustration, and almost nobody explains it before they need it. It applies to anything you do on BNB Smart Chain, not just to one programme.
What a gas fee is
A Blockchain is run by thousands of computers. When you send a transaction, those computers do the work of checking it and writing it into the permanent record. They charge a small fee for that work. That fee is called gas.
Think of it like postage. The letter is yours, but you still have to put a stamp on the envelope before the post office will move it. No stamp, no delivery, no matter how valuable the letter is.
The wallet guides supplied with this site instruct you to add the BNB Smart Chain network and to hold BTCB, BNB and USDT as BEP-20 tokens. The VALR guide walks through buying BNB specifically.
The rule that catches everyone
On BNB Smart Chain, gas is always paid in BNB. It cannot be paid in BTCB, in USDT, or in anything else. If your wallet holds no BNB, every transaction will fail, no matter how much of anything else is sitting in it.
This is the single most common way beginners get stuck. Someone buys BTCB, sends it to their new wallet, sees the balance arrive, and then finds they cannot move it, swap it, or use it for anything. The funds are not lost and nothing has gone wrong. The wallet simply has no stamps.
Why it feels so confusing
Three things make this harder than it needs to be:
- Receiving is free, sending is not. Tokens can arrive in an empty wallet with no BNB at all. The sender paid that gas. The moment you try to send anything out, you are the one paying, and that is when the problem appears.
- The error messages are unhelpful. Wallets often say something like "insufficient funds for gas" while showing a healthy balance on screen. It reads like a contradiction. It is not. It means insufficient BNB, not insufficient tokens.
- Approvals cost gas too. Before a smart contract can move a token on your behalf, you sign a one-off approval. That approval is itself a transaction and costs gas, so interacting with any contract usually costs gas at least twice.
How much BNB to keep
BNB Smart Chain fees are typically a very small fraction of a BNB per transaction, but the exact cost moves with network demand and with the BNB price, so no fixed figure stays accurate for long. Check the live gas tracker at bscscan.com/gastracker rather than trusting a number written down months ago.
The practical habit: keep a small working balance of BNB in the wallet at all times, and top it up before it runs dry rather than after. Running out mid-task is what causes the stuck feeling.
Never empty the wallet completely. If you send out every last bit of BNB, you have no gas left to send anything else, including the other tokens still sitting there. Always leave a working balance behind.
Getting BNB into your wallet
Buy BNB on an exchange
The VALR guide covers this for South African users: deposit Rand by EFT, search BNB/ZAR in Markets, and buy. Binance works the same way.
Check the network before withdrawing
When withdrawing to your own wallet, the exchange asks which network to use. Choose BNB Smart Chain (BEP-20). Choosing the wrong network here is the most expensive mistake in crypto, and it is usually not reversible.
Send a small test amount first
The SafePal guide makes this point and it is worth repeating. Send a small amount, confirm it arrives, then send the rest. A test costs you one small gas fee. Getting it wrong can cost everything you sent.
Confirm BNB shows in the wallet
Once BNB appears, your wallet can pay for its own transactions and everything else becomes possible.
A checklist before any transaction
- Do I have BNB in this wallet, not just tokens?
- Am I on BNB Smart Chain, and does the receiving address expect BEP-20?
- Have I sent a small test first if this is a new address?
- Am I leaving enough BNB behind to pay for the next transaction?
One safety point that never changes. Paying a gas fee never requires your twelve-word recovery phrase. Nothing legitimate ever does. If a website, a person, or a support agent asks for your twelve words to "unlock" funds or "cover fees", it is theft, and both wallet guides in this site say so plainly.