I've written a script to buy tokens in javascript. The issue is I keep getting an error showing abnormally high transaction fees. This is my script

const buyFunction = this.pancakeContract.methods.swapExactETHForTokens(
    this.w3HTTP.utils.toHex(this.w3HTTP.utils.toWei('0', 'ether')), // amountOutMin: set to 0 or calculate based on slippage
    [this.config.constants.liquidityPairAddress, tokenAddress], // path
    this.config.settings.walletAddress, // to: Recipient of the tokens
    Math.floor((Date.now() / 1000) + 60 * 2) // deadline: Current time + 2 minutes
  const nonce = await this.w3HTTP.eth.getTransactionCount(this.config.settings.walletAddress)
  const amount = this.w3HTTP.utils.toWei(amt, 'ether');
  const gasPrice = this.w3HTTP.utils.toWei('3', 'gwei');
  const gas = this.w3HTTP.utils.toHex(Number(config.settings.gasAmount));
  const walletBalance = await this.w3HTTP.eth.getBalance(this.config.settings.walletAddress);

  const rawTransaction = {
    "from": this.config.settings.walletAddress,
    "gas": this.w3HTTP.utils.toHex(gas),  // 250,000Wei
    "gasPrice": this.w3HTTP.utils.toHex(gasPrice),

  const signedTx = await this.w3HTTP.eth.accounts.signTransaction(rawTransaction, this.config.keys.walletPrivateKey);
  // console.log("signed tx: ", signedTx)

  const receipt = await this.w3HTTP.eth.sendSignedTransaction(signedTx.rawTransaction).catch(console.log);

When I run this, with an amt value of 0.0000001BNB I get the error

'err: insufficient funds for gas * price + value: address 0x700C9A0c93616918E2685b4cf5115e26C8d2DF74 have 23129168874516353 want 87741903484150489762066983472 (supplied gas 300000)'

Why do I get these abnormally high transaction fee? Could I be using the wrong units in the rawTransaction?

1 Answer 1


When setting amount, I decided to set its type to Number like this

const amount = Number(this.w3HTTP.utils.toWei(amt, 'ether'));

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