There are currently two main types of domain speculators: those that buy domains, build sites around them, and then flip the domain and accompanying website, and then there are those that buy and sell domain names without web sites attached. While both can be very lucrative businesses, the second type is much easier for novices to learn, and as such, shall be the topic of discussion for this article. 
Since 2013, more than 183 million domain names have been registered but none of these is used. A large chunk of these domain names is hoarded by domain flippers who will then resell these domain names to new buyers. Now if you are a newbie in this particular field, the best way to go about flipping domains is to start with a small budget until you gain relevant experience in the field.
Most of the website owners interested in an expired domain that has existing traffic, backlink and good SEO metrics. This kind of domain more likely gets buyer easily since it has a plus value for search engine optimization purpose. You can find high-quality expired domains that have SEO metrics by using BuycomDomain - The Expired Domain Search Tool for free, as seen in the picture below.
In theory, you could technically acquire a domain for $10,000 and be able to sell it for $100,000. You could also acquire a domain for $10 and be able to sell it for $100,000, $10,000… or $100, you get the picture. Because of this, it’s hard to recommend a perfect starting budget because your strategy, experience, and the pace at which you learn will hugely affect your buying and selling decisions.