## Newbie in the crypto world must know: Why is it that buying and selling coins is always more expensive?

Friends who trade at Gate Square have all encountered this situation - you want to place an order to buy Bitcoin for 10,000, but it ends up being 10,003; or you sell a small coin, and the price inexplicably slips to a lower level. This is **the difference between buying and selling** and **slippage** causing trouble.

**What is the buying and selling spread?**

In simple terms, it's the gap between the seller's asking price and the buyer's bid. For example, if someone is bidding 69999 dollars for BTC and another is asking for 70001 dollars, the difference of 2 dollars is the bid-ask spread.

Major cryptocurrencies (BTC, ETH) typically have a spread of less than 0.01% due to high trading volume and good liquidity; however, some smaller coins can have a spread of 1-5%, causing the price to spike as soon as you make a purchase. This is because there are fewer people willing to take orders in the market, and sellers have to raise prices to attract buyers.

**Slippage is even worse**

When you place a market order to buy 10,000 of a certain coin, but the market doesn't have enough inventory to fill your order at the desired price, the system will continue to sweep up orders, and you may end up spending 10,500 to complete the transaction—this additional loss of 500 is called slippage.

The small coins have the highest slippage on DEX, sometimes exceeding 10%.

**How to avoid these two pitfalls?**

1. **Split Orders**: Instead of buying a large amount all at once, divide it into several smaller orders, purchasing a little at a time to reduce the impact on the price.
2. **Use limit orders**: Don't pursue speed, set the highest/lowest price you can accept, wait for the transaction to complete. It's steady, but it might take a while.
3. **Check Depth**: Before trading, take a look at the order book. If the depth is shallow (not many orders on both the green and red sides), it indicates that this coin has poor liquidity and carries a high risk for large transactions.
4. **Choose mainstream coins**: BTC, ETH, and USDT are liquidity monsters, and the spread and slippage can almost be ignored.
5. **Set Slippage Tolerance**: When trading on a DEX, you can manually set the maximum slippage you are willing to accept to prevent being targeted by sniping orders.

**Final Ramblings**

Price differences and slippage may seem like minor issues, but during large transactions, this cost can eat away a significant portion of your profits. Especially when trading new coins on AMM-type DEXs, you must calculate clearly; otherwise, the probability of being trapped is extremely high.