Little known fact ... many of the off-brand tabled are rooted out of the box. The problem is there's just no way to tell unless you happen to be lucky enough to find someone who already owns one and is willing to check. The second problem is there's virtually zero support from the manufacturers, assuming you can identify them and find a contact who actually responds to questions. Finally, because the cheap tablets are a mish-mash of components and generally not kept very long, there's never been much development community interest. So, if it's not rooted, and one of the generic root methods don't work, you're pretty much stuck. And, trying to root it in the first place might make it un-returnable.
Instead, you might look for refurbished brand name tablets. They might cost a few dollars more, but you won't be left twisting in the wind with your first problem.
