The first thing you need to do is signup at Namejet in order to get your account (signup is free). You can then use their search functionality to sort through all the upcoming domains for auction. Place bids for $69 on the ones you want to go to auction for. If you bid on 100 different domains for $69 each, and there is 50 bidders for each auction you need to understand you aren’t going to owe any money, you are not committing $6,900 to Namejet. By entering that $69 you are getting an entry into the live bidding when the 30 days expire. Only if you are the ONLY bidder on a domain would you automatically win the domain and owe $69 to Namejet.
We do not only have Expired Domains, but you can also find lists of Deleted Domains for a lot of TLDs. Deleted Domains or Dropped Domains are available for registration and can be picked up for just the normal regfee at your preferred domain registrar! All Domains have the typical SEO relevant data, like Number of Backlinks, Archive.org Birth Date and a lot 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.