They sell for less than $100 (if they sell) with lifetime on eBay. It is not worth paying $99 to sell it for less than that. The only ones getting more than $100 have upgraded hard drives in them. Without lifetime and a stock hard drive (and a broken DVD drive), you can expect to get about $5-15 on eBay unless you get really lucky.
If you don't want to trash it, list it on craigslist or freecycle and let someone pick it up for free.
TiVo Mini X 3
Left DirecTV 4/15/07. Left TWC 8/8/11. Now on Comcast Xfinity.