Your course of action really depends on how much work and effort you can put into the expired domain. If you're barely able to maintain and optimize your current site, you probably want to just 301 redirect the old site (note: see my amended comment above about the link value not likely to be passed). If, however, you're more creative and have some time on your hands, you can try your hand at crafting a microsite. If you really know your stuff and are experienced at making money off various websites, you'd probably do well with the third option.
There is a misconception that good ‘.COM’ domain names are hard to find and so they are more expensive to buy. But once again, this statement holds no water. You can easily check out the ‘.COM’ domain names that are on sale at highly affordable prices. However, the only downside to flipping ‘.COM’ domain names is that you will have to discover them at different places like Flippa.com or private seller portfolios.
Here's a test I have in process. I bought an old $5 closeout domain from Godaddy TDname expired auction. I put a quick minisite up and linked to it with a crazy anchor text phrase. The domain is ranking for that crazy term now. It's gone through one pagerank update and I'm waiting for a second to come. Then I'll redirect the domain to another minisite. I suspect the second site won't rank for the anhor text, but we'll see.
Current Craze: When PokémonGo was HUGE last year, my domain flipping friends (Matt of Handshakin.com is one) were all about buying domains like PokeStopNearMe(.com) and other related domains associated with the PokémonGo craziness. It’s like the day trading of the domain world. You’re buying domains during the hype and hope to sell them for a higher price quickly before the hype fades.
Determine your domain's value. Before you start taking offers or listing your domain, take stock of its value so that you can come up with a good price. There are a lot factors to take into consideration when determining the value of a domain, so if you are unsure it may be wise to contact a company that performs these assessments. Some of the major factors include:
Before you park any domain names, you must focus on finding hot keywords that buyers would be interested in. The best way to make sure you get a good return on your investment is to pick a domain name with acceptable traffic, somewhere around 10,000 searches a month. You can do this conveniently by using tools like Google Keyword Planner or Niche Finder Software.
With over 25 million .com domains registered with Google alone, this top-level domain is by far the most popular choice worldwide. According to the domain marketplace Sedo, the average sales price for a .com domain name during the second quarter of 2015 was 4,701 dollars. The most expensive publicly traded domain names have been known to fetch eight-figures. But don’t quit your day job just yet: such sales are the exception rather than the rule.
In the past, expired domains were used as part of black hat SEO in order to generate backlink sources quickly and easily, and this practice is still used somewhat today. Getting links in this way is not a recommendable practice. All relevant search engines work nowadays with highly complex ranking algorithms, which can no longer be outsmarted by these link networks.
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.