Another point of concern is that many people feel that squatting or registering domains is unethical. This is because many web developers have a hard time finding relevant domain names for their projects since most of them have already been registered. Many corporate giants also frown upon the domain flipping industry because many domain names relevant to them are already registered.
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).
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”.

Internet users, who try to find expired domains and re-register them, will soon discover that this plan cannot be manually accomplished. Professional domain traders are familiar with the registry deletion process and rely on sophisticated algorithms that indicate when a domain is about to become available. Deletion lists are the result of this research. You can find many datasets online with domains that have already become available or will soon be. You often have to pay to be able to see this information.
That said, my recommended budget for beginners would be $500+. Using this budget you could buy a bunch of high-potential $10 domain names, expired/dropped domain names or a mix of both. It’s very important to invest only what you can afford to lose and treat this as a side hustle till you get the momentum going. As you gain experience, industry expertise and some sales under your belt, you can then consider slowly growing your business into a full-time gig.