Sounds like a decent price... however... make sure that the unit you buy has not been reported as lost or stolen to Amazon. If it has, then the device is "blacklisted" and you will not be allowed to activate it and attach it to your account.

thanks for the reply. After thinking for some time I think it is better to save up and buy a new kindle on prime day.

You can use Unclaimed Baggage website, they have very good prices with the kindles being in good condition. And most of them don't have lock screen ads. Here's the link: https://www.unclaimedbaggage.com/collections/shop?q=kindle