But in general, the best and easy way to sell a domain is to go with a marketplace. There is many popular marketplace dedicated to selling domains including Flippa and SellDom to sell your domain (full disclosure, I’m working on SellDom). The advantage is to leverage the popularity of that kinds of services in hope that someone will find your domain and buy/make an offer.
I don't necessarily agree with some that dropped domains don't have value for SEO purposes but either way one thing you can do is to check out our tool for finding auction domain names (the tool has a database of domains available buy from GoDaddy and SEDO and also give additional SEO criteria to look up for the domains like backlinks, Compete data, CPC, Google stats, Alexa stats, etc. and there is also an option to schedule auction domain alerts so that you can be notified via email if a domain name meeting criteria you specify gets put up for sale) or you could use our tool fo domains dropping soon that shows all domains dropping in the next 5 days that way you can be ready to snap them up right away.
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
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.