I'm going to reveal something that is so simple, most people overlook it. Check your Flatscreen to verify that it has an HDMI input on the rear. If it does, and you do not have an HDMI cable, take a trip to Marshalls, Target or BestBuy and purchase one. From your laptop or SmartPhone, it is possible to connect the HDMI to HDMI, or mini HDMI to HDMI cable to your Flatscreen. Once you do this, your Flatscreen instantly becomes a jumbo computer monitor. Obviously, you will need to toggle between HDMI 1 and HDMI 2, or Cable on your Flatscreen depending on how you set it up. Don't worry if you don't have a 4K super hi resolution Flatscreen. I'm using an 720p in my office and an 1080p in my home and they both look stunning as you can see on the above image. The monitor above is a 42" Vizio that cost less than $300. There are two devices pictured on the right below the speaker. The one on top is the Mac Mini. The one on the bottom is my Router/Time Machine which is not needed for this operation. Also pictured is my bluetooth keyboard and mouse.
I decided I wanted a permanent solution for both my home and office. After doing quite a bit of research, I discovered that as of June 2010, and after, all of Apple's Mac Mini models included an HDMI port. I found one from late 2010 on e-bay for $250. I also found an Apple WIreless Keyboard and wireless Mouse for another $100. These I used in my living room. This solution worked so well, on my 55" living room flatscreen that I figured why not utilize the 42" TV in my office and "create" a 42" Mac Mini. The above is a picture of that set up. Nothing like viewing photos, streaming video, reading e-mail or using social media on a humongous screen.