You can use pancakeswap API for get coin price in USD and convert it in your application

Simple example

const PANCAKESWAP_TONCOIN_ID = '0x76a797a59ba2c17726896976b7b3747bfd1d220f'
const PANCAKESWAP_URL = 'https://api.pancakeswap.info/api/v2/tokens'
const UPDATE_ERROR = "Can't update token price"


await new Axios({})
  .get(`${PANCAKESWAP_URL}/${pancakeswapTokenId}`)
  .then(async (response) => {
    if (
      response.status === 200 &&
      response.data &&
      parseJSON(response.data)
    ) {
      const { data } = parseJSON(response.data)

      if (data.price && validateThirdpartyPrice(data.price)) {
        resolve({ price: data.price })
      } else {
        resolve({ error: UPDATE_ERROR })
      }
    } else {
      resolve({ error: UPDATE_ERROR })
    }
  })
  .catch(() => {
    resolve({ error: UPDATE_ERROR })
  })

As you can see in data.price you will get value like: 2.42187 (Toncoin in USD)