Another thing to factor into your purchasing decision.
How many TLDs are registered for given keyword(s). If .net is available for hand reg and 10+ TLDs are taken, that COULD be a sign of value. Not always the case, but as a general rule of thumb the more TLDs regged (and length of registration) the more valuable the domain is.
Who values the domain at $30k? Not to pump up companies like BrandBucket, but generally their $XX,XXX+ domains are good enough quality to consider other TLDs. (By no means should this be your only factor) For example bb has HalfCourt.com published for $28k. 5 HalfCourt.TLDs regged. 0 registry premium. The .net has been regged since 2014. There are 2 .total nets regged containing HalfCourt. Not a must have .net but but good enough for somebody to hold for a few years. A better example might be Namerific selling Broth.com for $25k. 18 Broth . TLDs are registered + 200 Broth . TLD considered premium by registries. As expected, Broth.net has been registered for a while (since 2003). Not to mention 500+ .Net's contain broth.
There are other factors, mainly acceptable uses of the domain, to consider when assigning value. Hopefully this helps a little. Feel free to comment / debate anything and pardon any grammatical errors as this was written via my mobile while at the dentist.