example tx to send cUSD using cEUR as tx fees.

sendcEUR.js

const Web3 = require('web3')
const ContractKit = require('@celo/contractkit')
const web3 = new Web3(`https://celo-alfajores--rpc.datahub.figment.io/apikey/${process.env.FIGMENT_API_KEY}/`)

async function sendCELOTx(){

    // Connect to the network and get the current tx count
    let nonce = await kit.web3.eth.getTransactionCount(kit.defaultAccount)

    // Send 0.1 CELO
    let amount = kit.web3.utils.toWei("0.1", "ether")
    
    let CeloTx = {
        to: "0x9a8e698171364db8e0F5Fe30f658F233F1347F6a", // omit recipient for a contract deployment
        from: account.address,
        gas: 200000,               // surplus gas will be returned to the sender
        nonce: nonce,
        chainId: "44787",          // Alfajores chainId
        data: "0x0",               // data to send for smart contract execution
        value: amount,
        
        // The following fields can be omitted and will be filled by ContractKit, if required 

        // gasPrice: "",    
        gatewayFee: 0,       
        gatewayFeeRecipient: "",
        feeCurrency: "" // optionally set feeCurrency, ie "0x10c892A6EC43a53E45D0B916B4b7D383B1b78C0F"
    }

    let stabletoken = await kit.contracts.getStableToken()

    await kit.setFeeCurrency(ContractKit.CeloContract.StableTokenEUR)

    let tx = await stabletoken.transfer("0x9a8e698171364db8e0F5Fe30f658F233F1347F6a", amount).send({ from: account.address })

    let receipt = await tx.waitReceipt()

    console.log(`CELO tx: https://alfajores-blockscout.celo-testnet.org/tx/${receipt.transactionHash}/token-transfers `)
}

 sendCELOTx()