Add On checkout service

[geoso_8250]

How to add on service at check out time for a particular product?

[slippinjimmy]

You can't!

The only thing you can do is create a separate listing for the service and tell buyers to purchase the Item and the service if they desire  it.

[pburn]

Are you asking about adding your own "service" for a product? Like a warranty service of your own? I don't think that's something you can offer members who buy your product, but I'm not sure. I've not heard of anything like that, anyway. 

eBay has its own warranty coverage called SquareTrade for eligible items, as well as a Certified Refurbished Warranty.