I'm leery of cheap HobbyKing products for which a review on HK's own site includes the phrase, "burst into flames." As well, in general with HK, you can expect no warranty or other post-sale service on that.

However, if you're willing to treat it as a use it-toss it if something goes wrong product, you could wind up with a bargain.

But before buying that, I would recommend taking a look at HobbyWing's combos for something that will probably be a little more robust product but with some savings still over the Castle stuff.