Keyword relevancy is not the only thing that matters when it comes to SEO. However, domain names that were previously used by other businesses usually have a lot of backlinks and a decent ranking on PageRank. Even though such domain names are usually about to expire, they are still worth a lot of money if they have a good number of backlinks and a ranking of five or more.
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.

Don’t get me wrong, I’m not saying marketing your domain is not important. But, if you’ve bought a bad domain and you do (and overdo) everything laid out in this section and more, it’s still very unlikely that it would sell. It’s like spending car flipping and spending a huge amount of money, time and effort perfecting a car’s paint job, except that this car’s engine is completely fried. You’ll never be able to drive it anyway, no matter how awesome the paint job is, it’s irrelevant.

  Since starting SEO back in 2009, it has become very difficult to rank brand new domains. Unless you are building a brand, it's highly recommended that you start every new money site with an expired domain. Additionally, if you're building a PBN, you should only consider using expired domains. The problem is good domains start at $50 a piece, and anyone charging less is either full of sh*t or selling garbage domains, and I mean that. If it sounds too good to be true, it probably is. DomCop has a great offer that all of you buying expired domains should consider. For the price of a couple domain names, you can use DomCop for a month, snag some excellent domain names, which would otherwise cost you thousands of dollars. If you're considering expired domain software and don't have the knowledge to program your own crawler, I'd lean towards DomCop.   

Those trading domains for commercial purposes are generally on the prowl for lucrative domain endings. There are essentially two different ways traders go about making money off of domain names. One method entails purchasing already established names for a low price and selling them for a profit later once their value has increased. Another strategy involves buying and registering a domain that is thought to possess a high sales potential. Many domain traders use backorder services. These services automatically register a domain when one becomes available or is deleted (what are known as expired domains).
For the following TLDs you can now find a expired/deleted domain list. .gi, .gl, .gy, .hn, .ht, .ky, .mu, .om, .pf, .qa, .rw, .sb, .sm, .sn, .st, .sx, .tc, .tl, .ug, .uy They also show up in the Deleted Domains (last 7 days) list and in the Domain Name Search, however they are not in the pending delete list! I do not have a working droplist for them yet, so that is why they are not released in the pending delete list yet.
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”.