Just because someone spent five or six figure amount on a domain name doesn’t automatically imply that he/she’ll spend the same or at least a few thousand dollars on a similar name too. Basing your domain flipping strategy entirely on what others have just bought may not be as useful as you may think. Every domain name has a story behind it and its purchase/sale is usually as unique as that story.
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.