I use the Photosonix Nova Pro 100. Photosonix is the brand and the rest is a model number. I thought I got mine for about $300 a couple years ago, but I see it on sale now for $349. I got mine from a place called Tools for Wellness, which sells all sorts of odd, and some not so odd, wellness and consciousness related products. Their intro page on light/sound is at
http://www.toolsforwellness.com/light-sound-machines.htmlThey have a number of other L/S machines too, many at lower prices, but I'm not very familiar with most of them. I do recommend the Nova Pro 100 if you're willing to spend that much. The Muse and David lines have been around for a long time too, so they're probably good too but I don't really know them. It seems like they used to have a wider range of choices and prices than they do now.
I've never used any of the computer software that does similar things. I don't know if you get the kind of precise frequencies in both ears that you need for it to work. You need to use headphones to get the full effect. Also the visual probably helps a lot.
One reason I like the Nova Pro 100 is that you can create your programs on the computer and download them to the machine. The built-in programs for gamma range are not very good or plentiful. Seems odd because my older one that I got about 15 years ago had more and better gamma range programs. I think in the new model, they went overboard on glitzy and showing off some of its capabilities, and lost a lot in the quality of programs. But the older one was much more difficult to write your own programs for.
I'm not sure that it has helped me learn to enter the states without it. I've been a meditator for almost 30 years, so I enter the lower frequency states fairly easily, but it has helped to recognize just where I am, by noticing when I seem to be "with" the machine and what my sensations and thoughts are. It may have helped learn to go to those states more quickly. It doesn't seem to be a crutch, but then I regularly meditate without it, so it couldn't become too much of a crutch. Oh, also it can be a nice aid when I'm just not in the mindset to get into a state.
On the other hand, I don't know any tools or techniques to enter gamma states other than the machine. They're not well-understood states with a history of practitioners learning how to use them. After doing the gamma sessions a number of times when I got the "hot Reiki hands" phenomenon, I found that I could get the hot hands effect by just sitting and wanting to go to that state. Without an EEG, I don't really know if my brainwaves are there or not; even with most EEGs, I wouldn't know, because they don't typically measure that high.