@ejach2000 - The tradeoff decisions in making a magic mirror are basically as follows:
You can get a cheaper mirror surface by going with two-way acrylic. I used TAP Plastics and it worked okay. The two way glass produced better results, but you will have to decide if the difference is worth the extra cost.
The other option is to purchase a two way mirror film and attach it to a piece of glass. This way takes patience and practice, but it is a decent way to save money.
Don’t try to combine two pieces of glass into one mirror. The seam between the pieces will be very visible and will annoy you.
You do not need a specific monitor. There are features that make the process easier for you during construction. Most importantly, IMHO, is that the power and HDMI connectors point down and not directly away from the screen. Secondly is the ability to accept an HDMI connection (lack of HDMI can be overcome with adapters).
HTH.