Selling a Series 3 with lifetime - Suggested sales price? How to use ebay?

I had one lady send me the wrong Tivo and she expected me to pay shipping charges back. Finally she paid for it, but then she left a bad revue on me on ebay. She really put me through the ringer. And just this month a lady had a DVR listed in the wrong category and was nasty because it confused me. Friends of mine have got the wrong item and have had to go through $#%@ to get their money back, and have had people say they never got an item even though they have emailed before that they did get it. Ebay isn't very helpful in many cases, so I only use ebay when I can't sell items by other methods. Ebay has changed many of their policies in the last 5 years not for the good. But they do have a money back guarantee that makes it so I will buy from just about anyone and ebay will give me my money back plus shipping if there is a problem in most cases. That is the best thing ebay has done in a long time.
Be very careful as far as your listing. Many people new to ebay make all kinds of mistakes, and if you say it has something and it doesn't or you leave out something not working, or dents in it, you will probably pay for it. I have bought lots of things on ebay that were listed wrong. It worked out OK in most cases, as they refunded me some of the price to make up for the item being a lower model level than the one shipped. So we both were happy in the end, but I could have refused the item and then the seller would have had to pay to get it back. Irregardless if they list the item as 'no returns'. I told one guy 'oh, if you don't want it back, that is fine with me, but I still want my money including shipping returned.' Then all of sudden he wanted me to ship it back. And he paid to do it.
Be really good about answering questions on your listings too. Most people are terrible. Many times I ask multiple questions on a listing and the dumb lister answers 'maybe, in some cases'!!! Or they answer the questions days later after the listing is closed.