Office cubicle partitions were actually the first acoustical treatment I ever used. I'd gotten a bunch of them for next to nothing when the company I worked for went belly-up, along with some desks and chairs.
I found two things about them. First of all, different models and manufacturers use very different construction for what appear to be the same panels. You can tell which are the good ones by lifting it - not recommended for someone with a bad back, as they are extremely heavy. Those have a solid metal core inside; the cheaper ones that don't work as well have a kind of cardboard interior.
The second realization is that they are not the least bit linear in their absorption or isolation. They sound dead because they stop the upper midrange where most of your annoying office noises reside such as talking on the phone and fingers clacking on keyboards. But below about 700 Hz they do next to nothing.
If you buy them new they're quite expensive, putting even Auralex to shame on pricing. However, defunct businesses are liquidating assets all the time so bargains can be found. I think I paid 30 bucks for 8 panels plus two desks and four chairs. Here in the Seattle area, Boeing Surplus used to be a good source if you don't mind military-looking furniture.
The biggest upside is that they look nice. And you can hang shelves from them, that's another plus. But as an acoustical treatment they're just not terribly effective on their own.