Typically less than half a percent, often lower.

As far as I see, average ETH gas prices have been between ~20 and ~170 USD in the last few months. So, by my understanding (happy to be corrected) for a 1k USD transaction, that's between 2% and 17%. It does get pretty good if you're transacting huge sums. It's abysmal for day-to-day payments.

do you have any experience sending eth?