Almost all figure collectors use the word "bootleg" to refer to figures that are surreptitiously produced by various [Chinese] manufacturers, but I think that a more proper term taken from the Chinese would be "shanzhai".
Shanzhai is a term that has recently started to be used in English, and is literally translated as "mountain village" or “mountain stronghold”. It is said that the name is an allusion to the Water Margin (水滸傳), a classic 16th century novel about outlaws who establish their own mountain society in opposition to the central government.
The term was originally coined in Cantonese to refer to small family operated manufacturers who made various types of generic low-end or counterfeit products.
Since then, shanzhai has evolved to acquire new definitions that also connote imitation, parody, and improvisation. A couple of sites that have interesting articles on shanzhai include the Pacifica Literary Review, and IDEO.
Patchi (パッチ) is a similar term from Japan used to refer to knockoff products based on tokusatsu shows.
I like the use of the term shanzhai as opposed to bootleg because the manufacturers of these figures do not try to hide the fact that the figures are not authentic. The context is similar to the use of shanzhai to refer to celebrity impersonators. To me, true bootlegs attempt to disguise their origins.
The line between shanzhai and bootleg are blurred because of sellers (not manufacturers) who try to pass off both types of unauthorized products as authentic, but for most people I guess the point is really moot.
|★ ☆ Sader ♡ ♥|
The most [in]famous version of a shanzhai figure is "Sader", which was bundled as a bonus with an equally unauthorized Fate/stay night magazine. Aside from the crude appearance, there is no way the 3" tall figure would be confused with the original 1/6 scale Clayz figure, even if Sader looked more like her prototype.
True to the "so bad it's good" trope, Sader has gained a loyal following, and I have a feeling that her figure may even be more in demand than the original Clayz figure.
On eBay, shanzhai figures are described in the product description as "China Version", and are a fraction of the cost of an authentic figure. If you think the price is too good to be true, then you are probably looking at a shanzhai figure. Sometimes, the cost of the figure will be in proportion to how close the shanzhai figure is to the original in terms of materials and production quality, but the buyer will have to verify with pictures of the actual product.
I will often buy shanzhai figures for use in making conversions, or for replacement parts.
|Miku is missing a hand and needs a replacement.|
They are also good for use in gaming, since certain players can be heavy-handed or just plain jackasses when they handle figures.
Shanzhai figures are typically more robust than authentic figures, as they often are pre-assembled and glued together. This is an advantage, since figures like early Nendoroid Petits are not really suitable for gaming, because their limbs fall off at the slightest touch.
In any event, the producers of legitimate figure do not lose a sale when I buy a shanzhai figure. By the time I typically envision a conversion, the figures I want to use are already OOP and only available in the aftermarket.
Speculators and re-sellers may complain because shanzhai figures can lower prices in the aftermarket, but I could care less. If you want to invest in something, get into the stock market. The appreciation in value of an anime figure will do nothing towards your retirement plan.