A rule of thumb that I follow is when I purchase a domain name I have to believe that I can flip it for a 100% profit.  So if I spend $500 on a domain I need to feel like I can sell it for no less than $1,000.  This way, even if I’m wrong in my estimation I still have some room to still turn a profit.  And if worse case comes to worse case I’ve sold domains before for a $0 profit (it happens even to the best of us).

I have some pot related ones I've purchased recently that deal with the manufacturing of hemp like hempmfr.com, hempmoulding.com, hemp-textiles.com, hempecofuel.com etc.  Some of the older domains I've been sitting on are ones like internetpot.com, califunk.com, cafunk.com, caedibles.com, 1tokewonder.com, govherb.com, grasspeddlers.com, pot-megastore.com, usgov420.com etc.  Another interesting recent on I've purchased is Dogparkdates.com and dogpark-dating.com. Do any of these seem valuable in your eyes?

Once you get to this point you know there have been DMAS listed. They have a number of domains linking to them and according to the way back machine which is WBY, you can see their site age. So, if you want to go with an older site you can see right here whether or not this is a site that you might be interested in, but before pulling the trigger you do want to check two things.
2) prerelease auctions.  These are domains where the auction venue has contracted with the registrar, like Fabulous or Moniker, to auction off non-renewed domains.  Just before a domain enters the pending delete process, it goes to a private auction to any person who has backordered the name.  Some people feel that back links on these type of auctions still provide a SEO benifit. My testing indicates that there is zero SEO benifit when these domains are redirected into another site.  So if you get a domain with "pink squirels" in a lot of achor text to a domain and then point it at your domain, you don't rank for "pink squirels"

Determine your domain's value. Before you start taking offers or listing your domain, take stock of its value so that you can come up with a good price. There are a lot factors to take into consideration when determining the value of a domain, so if you are unsure it may be wise to contact a company that performs these assessments. Some of the major factors include:
They see a domain’s price tag and they can instantly tell whether it’s under or overvalued. This is probably the most important skill one should have in this industry. Neil Patel has an interesting related quote: “The most important thing to remember when buying sites is that you always make money on the buy, never the sell.” In order to successfully do this, you must be able to spot undervalued domains. This is what will ultimately translate for you into a handsome profit margin when you get the opportunity to resell the domain for its “real value”.