With account abstraction we want to give users who are new to blockchain as simple a user experience as possible. Showing the gas fee in USD rather than the native token will make it a lot easier to understand for newer users, and we can do this in a couple of simple steps. First we start by estimating the current batch of UserOps. This will be the units of gas used. 
const estimation = await primeSdk.estimate();
Then we want to get the gas in wei for this batch. 
const totalGas = await primeSdk.totalGasEstimated(estimation);
And multiply this by the current gas fees on the network.
gas = units of gas used * (base fee + priority fee)
const gas = totalGas.mul(estimation.maxFeePerGas as BigNumberish);
Next fix the formatting using the formatEther from ethers. 
const gasInMatic = ethers.utils.formatEther(gas);
Then get the current price of the native token to the network. 
const rateData = await primeSdk.fetchExchangeRates({tokens: [ethers.constants.AddressZero], chainId: 137});
Finally, multiply the current token price by the gas in the token to get the gas price in USD for this transaction. 
const priceInUsd = usdRate.usd * (+gasInMatic);