only google are evil enough to demand from people to have "clean" domains. In a normal society, search engines (and companies in general) have no business telling people what to do with their sites, domains and businesses, but unfortunately we don't live in a normal society and - what's worse - google still dictates everyone what to do if they wish to rank in their dying search engine.
So, if you intend to rank in google at some point, sadly, you do need to pay attention to which domain you buy because if you buy a spammed or penalized domain you will never rank in google. But otherwise, if you don't care about google (and you shouldn't care) and you wish to focus on non-google traffic sources like social media, Bing / DDG, PPC networks, forums, etc... it really doesn't matter which domain you use.
You can use
x.com (well, not this one because this belongs to Elon Musk, but this was just an example), or you can use
qrfqiwefdquiowehdfiqwueuiqwediuqwehgdq.com, it really wouldn't matter...
However, a few common sense tips to make your site stand out (because you do want people to easily remember your site so they can type it directly into their browser if they like it) are these...
- domain name should be short (anywhere from 1 letter to up to 8-9, even 10-11 letters is OK, the shorter the better of course)
- domain name should contain as few numbers as possible (a domain like diablo2.com would be OK to contain numbers since this - most likely - will be a site about diablo 2 so it's perfectly normal to contain the number 2... but generally speaking, you don't want numbers in your domain)
- domain name should contain no hyphens (because people don't like having to type hyphens, so it's better to have a domain like
carrepair.com instead of
car-repair.com, for example... If you like a domain so much but you can't buy it - because most good domains are already taken - you can buy one with hyphens, but if you fry your brains enough you might be able to find a good domain that has no hyphens, so try a bit hard initially
)
The TLDs (com, net. org, info, top, etc) don't matter most of the time. Google might penalize / cripple your site if you use .xyz (although I'm still not sure about this) because I've heard some folks say that google doesn't like .xyz domains because they're so cheap that spammers buy them in bulk and spam them all over the place.
So, if you wish, you can avoid using domains that end in .xyz, but other than this I think any TLD is valid, so you'll have plenty of options to choose from.
You said you wish to do sweepstakes (whatever those are), so try to see if the .sweepstakes TLD even exists. If it does, you could register a domain like
cool.sweepstakes... or
cheap.sweepstakes, or
my.sweepstakes, etc... Just get creative and I'm sure you will find a great domain name if you put a bit of time and research into it
One more thing... if you do intend to buy an expired / auctioned / non-dropped domain and you wish to rank this domain in google you need to do A LOT of research and checks, or else you might waste your money on a domain that will never rank in google...
But if you do wish to go with an expired domain then this list by Nargil will be a good place to start with the assessment of expired domains (but again, this only pertains to google, if you don't care about google at all you don't need to worry about this checklist):
https://www.blackhatworld.com/seo/what-is-your-checklist-for-domains-for-pbn.1342695/#post-14514468
