Domain name sellers are advised to use to list their domain name. The real advantage with is the mandatory escrow service that comes with every transaction. The site charges the seller a commission of 15% per transaction or USD 50, whichever is higher, for domain names featured on the site. Sellers who do not list with but would like to use their escrow service will have to pay the minimum transaction fee of USD 50, or 3% of the transaction, whichever is higher.
I'm not against making money in any way, but $400 doesn't really seem worth the effort and coffee expense invested (I like the good stuff). This is a very basic example used to put the costs in perspective. Most SEO providers charge more than $50 per hour, and you get what you pay for. The above example of a final labor estimate is probably much higher, or if the domain is already ranking high and the owner wants to sell, so is the initial purchase price. Since this is often repeated many times over for multiple domains, it could get time consuming, and expensive.
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.
There’s an important distinction to make here between domain flipping and website flipping. The latter mainly refers to buying and selling full websites. By full websites, I mean websites that actually have content and more often than not have traffic and revenue. When buying and selling websites, the domain name matters less as the main value there is the content, traffic, revenue, history/reputation, sustainability and growth opportunities. The same can’t be said for domain names where you’re just selling “the name” and hence it’s all that really matters.