If you’re serious about domain flipping, one of the best strategies is to buy expiring domains that auctioned on the market such as GoDaddy Auctions. Make sure you pick domain names that have good traffic, backlinks and SEO metrics, or domains with the generic niche. Expiring domains with a potential for profit can be found using BuycomDomain.com, this is a free website/tool that helps you sort through the domains by different metrics (age, traffic, backlinks, domain authority etc).
Building a solid domain portfolio is not a piece of cake; it may take you several months or years to achieve this goal but it will definitely be worth it in the end. When you are in the fishing phase, look at the potential of the domain name. Another common strategy used by seasoned domain flippers is to get hold of some high profile domain names and sit on them until they soar in terms of value.
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.