How to Make Your First On-Chain Swap for Under Ten Cents
A calm, step-by-step guide to your first swap on Base: what you need, what to check before you sign, what it really costs, and why ten cents is enough.
The first swap is the moment Web3 stops being something you read about. It's also the moment most people hesitate. It sounds expensive, it sounds easy to get wrong, and the wallet pop-up doesn't help.
The good news: on a network like Base, a first swap can cost less than a coffee refill, and the amount you trade can be as small as you like. In our city the first trading quest, First Exchange, asks for a swap of 0.10 USDC or more on Uniswap. Ten cents. This guide walks through that swap step by step, but nothing in it is specific to us. It's the same swap anywhere.
Why ten cents is enough#
A swap of ten cents and a swap of ten dollars prove exactly the same thing: your wallet can reach a real market, pay its own gas and come back with a different token. The size changes nothing about the skill, and it changes everything about how relaxed you are while learning it.
That's why our thresholds start so low. We don't want anyone to risk money to find out whether they like this. We want them to make the move, see it on the chain, and decide from there.
What you need before you start#
A self-custody wallet. On desktop, a browser wallet like MetaMask or Rabby works. On a phone, any wallet that supports WalletConnect.
A little ETH on Base. Every action on a network is paid for in that network's gas token, and on Base that's ETH. You need very little: a tiny amount covers several actions. The simplest route is to withdraw a small amount of ETH from an exchange straight to your wallet and pick Base as the withdrawal network. Bridging from another chain works too, it just takes one extra step.
That's it. You don't need USDC yet. The swap is how you get it.
The swap, step by step#
1. Start the quest first#
If you're doing this as part of a quest, open it and press Start before you do anything else. The check only counts activity from the block where you started, so a swap made five minutes before pressing Start won't count. It's the single most common reason a first check fails.
2. Open Uniswap on Base#
Go to the Uniswap app and make sure the network selector says Base, not Ethereum. The same wallet address exists on every network, but the balances don't: if you swap on the wrong one, you either pay a lot more gas or the button simply won't work.
3. Choose ETH → USDC#
Put ETH on top, USDC below, and type an amount worth a bit more than ten cents. Before you go on, check that the USDC is the real one. Token names are free for anyone to copy; the contract address isn't. Uniswap's default token list shows the verified USDC on Base, and that's the one to pick. Never paste a token address someone sent you in a chat.
4. Read the preview#
Uniswap shows what you'll receive, the minimum you'll accept if the price moves, and the network fee. On an amount this small, price movement is irrelevant. The network fee on Base is usually tiny as well: a few cents at most, often less than one.
5. Confirm in your wallet#
Swapping ETH for a token is a single transaction. Your wallet will show the amount, the network and the fee. It should not ask you to approve spending of anything at this step: you're selling ETH, which needs no approval.
You'll meet approvals later, when you sell a token like USDC back. Then the wallet asks for permission for the app to move that token. That's normal, but read it: a sensible approval names the token and, ideally, a limited amount.
6. Check it landed#
A few seconds later the swap is done. Your wallet shows USDC, and the transaction is visible on Basescan. That record is the point: anyone, including a game, can now see that the wallet really traded, without screenshots and without taking your word for it.
7. Verify#
Back in the quest, press Verify. If it doesn't tick right away, wait a minute and try again. Indexers sometimes lag a little behind the chain. If it still fails, the usual suspects are a swap made before Start, the wrong network, or a venue other than the one the task names.
What to check before you sign anything#
A first swap is also a good time to build habits that will protect you for years:
- The address bar. Type the app's address yourself or use a bookmark. Fake swap sites copy the design perfectly.
- The network in both the app and the wallet.
- What the wallet is asking for. A swap is a transaction with amounts you recognise. A request to "claim", "unlock" or "verify" funds by signing something is a red flag.
- Approvals. Prefer limited ones. You can review and revoke old approvals later on a block explorer.
We say the same thing about our own city: we never ask you to send funds or sign an approval to receive anything. The only signature at sign-in is a message that proves the wallet is yours. It costs no gas and moves nothing.
What it really costs#
For a first swap on Base you pay two small things: the network fee, which goes to the network and is usually a cent or less, and the pool fee, a small percentage of the amount that goes to liquidity providers. On ten cents, that's nothing you'll notice.
The bigger cost of a first swap is usually the gas you bring to Base in the first place, and even that is a small one-off. After that, the same ETH covers your next several moves.
After the first swap#
The first swap shows that the venue works. The second shows that you do. In our city the next quest, Back Route, is one more swap on Uniswap in either direction, and Second Market takes you to a different venue, Aerodrome, where the price is a little different. Seeing two prices for the same pair is the first real lesson in how on-chain markets work.
If you want to try it with a map that lights up as you go, First Exchange pays 60 points and opens three quarters of the city. Everything about how the check reads your swap is in Proof and verification, and the full list of Base quests is on the Base page.
For more on why we count real actions instead of clicks, read why on-chain quests matter.
