Though the cheapest Full HD 1080p home theater projectors are available for as little as $500, you get a significant step up in performance and features now that 4K home theater projectors have dropped below $1500. They can also easily light up a 135" diagonal screen, or even larger. A 135" screen is almost 10 feet wide and 53.6 square feet, about four times the size of a 70" flat panel TV. So the projector delivers the true movie theater experience that you cannot get from even the largest TVs.
Thinking about a projector vs. a TV, another key difference other than dramatic picture size is the quality of light. In a commercial movie theater you get natural, balanced, reflected light. If you want to replicate that experience in a home theater, the projector + screen is the only way to do it. Flat panel TVs emit a lot of light per square inch and are great for lights-on video in a multipurpose room. But in a darkened viewing room that replicates the "movie theater" experience, TVs have a harsh glare that is not at all like the quality of light in a commercial theater.
For the genuine movie theater experience in your home, check out the best selling home theater projectors under $1500.
For other budget ranges see these Top 10 rankings: