You can turn then into content sites, set up an actual website, or try to sell that site elsewhere. You may even luck out by selling a site that's up and running and full of great content already. In this case, you can ask a higher price. Or, you can set up a shared hosting or direct hosting website. Shared hosting and direct hosting websites can be profitable too.
At the end of the day, the owner of this domain name let it expire and didn’t renew it. So while there may be many legit reasons as to why they might’ve done that, one of the not-very-legit reasons could be that the domain is “dead” in some way or another. In other words, it’s no longer useful for the original owner because of a penalty or otherwise. If so, it's unlikely it'll be of any use for you as well.
You can still buy two word or three word domain names incorporating your target keywords. Moreover, there are millions of domain names out there which haven’t been used at all and are bound to expire soon. All such domains keep coming back to the domain marketplace. What more, there are useful tools available to research and filter through such expired domains.
You can’t tell us (with a straight face) that aged dictionary word .net and .org domains won’t sell easily. The .net extension is technically OLDER than .com, and holds an equally intrinsic value to that of its .com counterpart. These LLLL .com’s that are just letters slapped together may be cute to look at and easy to sell, but in the eyes of Google, ANY aged domain that makes sense (i.e. a dictionary word) is going to be much easier to rank for than some acronym or hodgepodge .com…and at the end of the day, that holds more value than whatever society sees in these nonsensical “wqij.com” names.
Domain investors build a portfolio of valuable domain names, and attempt to sell them at a profit. Both Sedo and Afternic offer domain marketplaces (also known as Domain Listing Services, or DLS) for investors to advertise their domains to potential buyers. Once the seller and buyer agree, the aftermarket platforms then facilitate the purchase and transfer of the domain(s). As an Enom customer, you’re entitled to list your domains for sale on Sedo, Afternic, or both at the same time. Get started
Aside from places where you buy and sell domain names, there are some companies around that support the business of domain flipping. GoDaddy is one of the bigger names out there that does. There, you can not only trade domain names but also park those you’ve bought. The buying, parking and selling is relatively painless and all you must give up is a small percentage of your selling price.
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.