You've sold items in the past, so I'm quite surprised you didn't know there were fees as you were certainly charge them on your previous sales. The percentage has always been about 13.4% for the most part. You may only be realising it now as there is no more Paypal for sellers. Before, the fees were split between Ebay and Paypal, but now there is only one fee deduction upfront and it's handled by a company called Adyen, which is why it may seem like you're paying more, but you're not.
The $80 fee will be the least of your problems if you haven't been signed up, ID and bank verified for the Managed Payments system which has been in place for almost 3 years.
Once you are verified, you will need to wait around 20-30 days for your nett funds to be sent to you as you are an infrequent seller. However, you still need to post (preferably with tracking) within your handling time. Whilst you don't technically need to send with Signature on Delivery as the item is valued under $750, it may be worth your while as there are many scam buyers out there and it is a high value item.
I would strongly recommend you do some reading of the sellers guide, especially the new payments system and your seller obligations.
