Back in 2011 when I started developing Sleep Bug the sleepbug.com domain was unavailable. Actually it was registered in May 2010, so I was one year too late. Since the .net domain was available we registered this and have used it since then.
In the end of 2012 when Sleep Bug was starting to generate a very good income I thought about purchasing the .com domain, but I thought it would be too expensive (in the $2000-$3000 range).
When I was working with Sleep Bug one night in late 2015 I decided too look more into acquiring the .com domain. It has always been a dream and Sleep Bug has generated a large amount of money over the years, so I decided to look into it. I found the email to the owner of sleepbug.com and sent him an email asking if he was willing to sell it.
He replied that he was interested and we agreed upon $400 dollars, which I thought was a good deal. The person who bought the domain in 2011 had never used it. Originally he wanted to start an insomnia blog but he stopped pursuing the idea.
There are a lot of web sites that estimates the value of a domain, and sleepbug.com was estimated in the $400 dollar range (Estibot). Since I am using it to promote my app it has a lot more value then the parameters that gives you the estimated value. So I was really happy.
I am hosting my web site at GoDaddy, and since he also registered his domain using GoDaddy it was really simple to transfer the domain, but the fee is pretty high (I think it was around $70). When I called GoDaddy the customer support advised me to ask the seller to auction his domain (on GoDaddy), and then immediately bid on it (to reduce the cost). This seemed fairly risky, as I know there are a lot of people scouting 24/7 for new domains. There are a lot of other services you can use (e.g. escrow), but I decided to just transfer $400 dollar to the owner. I was pretty sure he was trustworthy, but for others I would advise you to be careful (at least if we are talking about high figures).
I have also redesigned my website as the previous did not support mobile devices. I am really happy about the result and I hope you like it too.