Firstly, are you talking about a "real" levitation such as floating a person in the air on stage (Aga, Asrah, Astro, Kellar, Kalanag)? OR, are you talking about the latest variation of standing on your tippy-toes?
Not to sound too crass, but the majority of the street levitation bits are simply waaay over-priced for what they are. . . variations to the Balducci technique what was for most accounts, a simple parlor GAG and not some kind of "show stopper" such as it has become due to the antics of David Blaine & Criss the 40 year old goth child...
My strongest recommendation is that you physically check out such devices BEFORE buying them. This is not uncommon procedure in the grand illusion world... think of it as you would buying a car (and big illusions do come with a new car price tag so you know they are inspected and compared). Get to the local IBM/SAM Groups and see if anyone has one of these new bits, which one(s) and get their feedback as well as a literal look at the device/set-up (most pros won't mind so long as they know that you are a committed and serious performer and too, you are committed to purchasing one or two systems for yourself in the near future... they might even offer you theirs for a reasonable price or allow you to "rent" the thing so you can try it out).
I know this sounds as if I'm encouraging some odd sort of "exposure" but that's not the case. If you are serious about doing the work you need to know which "tool" is going to serve you best under the conditions you are or plan to work the most, it's that simple... it's always why I (amongst others) frequently own two or more variation to the same effect; the performance conditions may be different and too, we might be working for the same audience base and therefore need to "change up" in order to throw off those trying to figure out things... and any levitation is something "they" want to figure out.
As to Grand Stage Levitations. . . regardless of which version you go for, you are talking about some serious cash layout, even if it's used. A piece like the Gomolo or Lighter Than Air will easily cost over $2k now days USED! (I do not believe there are any legal versions in production these days). A simple Super X Suspension is going to cost you right at $150.00 or so to make (if you do it right). The thing is, there are variations to all of these and you need to be educated as to which is which and which is the most dependable as well as practical. The Blaney Suspension for an example, is a huge leap forward from the Super X and yet, it is still based on the Super X and Harbin Suspensions that came before it, which is why it is superior to both.
While I'm not overly knowledgeable when it comes to all the "Street Magic" type levitations I can still give most a good run for their money when it comes to grand stage props, so if that's the course your heading to, feel free to ask me any questions you may have.