If you’re patient enough, you can discover at least four to five very good .COM domain names at attractive prices. However, you’ll need to carry out some research and find out the right places where they may be available. I’ve seen that such .COM deals can also be bagged from popular domain marketplaces like Flippa.com, or from the private portfolio portals of sellers, provided you employ the right strategies. You can contact the domain owners directly too. There’s no harm in emailing them directly to negotiate the prices.
Check DA/PA: The “Domain Authority” and “Page Authority” metrics gained significant popularity over the last few years. They seem to correlate well with a domain’s ability to rank in the search engines and hence, a domain having a high DA/PA will typically have a higher value. This is not to say domains with low DA/PA can’t sell for a lot of money because, at the end of the day, it’s just one factor. However, it’s good to take a look at these as they may tip the scale in favor of or against some buying decisions.

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.