"Best" and "Most Economical" are pretty much mutually exclusive. BEST would be a Christie 4K 3D digital with animorphic convergence. That is Soooooo not economical (north of $250,000.00). The most economical would be a Torpedo (a child's toy that uses cheap bulbs and is quite dim and very low resolution) at less than $100.00 new. The question is do you NEED HD or greater than a 300" (diagonal) screen? If the answer to both questions is no, I would recommed the Sony VPL-CS7 projector which can be had used for around $100.00-$150.00. The picture is clear and bright and it will project an image up to 300". I have one of these in my bedroom and the picture is quite good. If your budget is better and you need HD, look into the JVC DLA series of projectors.