I built a rack out of 5/8" threaded bar and MDF that definitely improved the sound of my system, but it has taken a while to get everything working together the way I like it. For example, the turntable is on the top shelf at a height of about 4 feet from the floor. Reading another post someone stated that a turntable high off the ground is bad, but I have tried it at other heights, including the bottom shelf, and the top shelf is by far the best place for it. I do have some massive brass cones underneath a 2 inch thick slab of maple, which really made things come together.
I think the best thing to do is experiment with things until you find the best sound. I do not believe you need to spend a lot on a rack, but someday I would like to buy a really nice rack for my system. I just don't have the space for one right now. When I do buy one I will place aesthetics pretty high on my list, with performance being the most important aspect. Right now my listening room is far from pretty. My dream is to have a listening room that sounds great but is also the ultimate man cave.
I think the best thing to do is experiment with things until you find the best sound. I do not believe you need to spend a lot on a rack, but someday I would like to buy a really nice rack for my system. I just don't have the space for one right now. When I do buy one I will place aesthetics pretty high on my list, with performance being the most important aspect. Right now my listening room is far from pretty. My dream is to have a listening room that sounds great but is also the ultimate man cave.