Prototype

You can't get Bumblebee's hardcopy in the market NOW! Woh!!!

A prototype is a sample version of a manufactured object produced for internal use in the manufacturing process, before the official mass production run starts. Various sorts of prototypes exist, both for the toys themselves and for the packaging.

Toy prototypes

• Mock-ups are rough models used to prove a design (not unlike fan-made kitbashes or "scratch-builts"), and may be significantly different from the finished product. They usually don't transform yet; instead, individual mock-ups are made for each mode.
• Hardcopies are hand-sculpted pre-production casts which are usually made out of resin and are used as the basis from which the injection molds for the actual toys are cast. As a result, hardcopies often have very much sharper detail than the final products. Hand-painted hardcopies are also used for the promotional photos depicted on the toys' packaging, which is why those photos sometimes look different from the actual products.
• Test shots, also referred to as engineering pilots or first shots, are basically test runs of the injection molds to test the tooling and spot sculpting errors, test the plastic tolerances, the articulation, etc. Safety testing is also done with test shots, which sometimes results in the injection molds being retooled or the plastic type used for certain parts being changed in order to accommodate the changes demanded by the legal department. They are often cast in a single color of plastic, or in seemingly random colors that look nothing like the final products. Some are completely or partly made of clear (but not necessarily uncolored) plastic, which helps the designers observe the functioning of hidden parts. First shots do not sport any factory-applied paint applications yet.
• Pre-production samples, also referred to as final engineering pilots (and sometimes also as "test shots" among fans), are very similar to the final products. They are usually cast in the correct plastic colors for the individual parts (although sometimes the plastic colors or shades can still be changed very late in the production process, sometimes even after the production run for the toy has already started, thus resulting in a running change variant of the official production version) and feature factory-applied paint applications, and their primary purpose is to provide an idea of what the final toy will look like and receive final approval from the company (or possible licensors). They are also used as display exhibits at toy shows. In instances where the samples don't sport factory-applied paint applications yet, they are hand-painted. Because pre-production samples are that similar to the final product, they will often get stamped with "not for sale" markings or feature deliberately wrong paint applications (e.g., wrong, upside-down or incorrectly colored faction symbols) in order to prevent them being confused with the final product.
• Production samples are the final stage before the actual production run starts, and are virtually indistinguishable from the final products in most cases. They are packaged in sample packaging (see below), and people with good contacts to Hasbro sometimes receive production samples for review purposes.

Packaging prototypes

• Mock-up packaging is often made of a random piece of cardboard (sometimes any packaging from another line that happens to be available in Hasbro's offices at the moment) with a clear plastic tray and window (or, in the case of carded toys, a blister bubble). Its primary purpose is to get an idea of the intended shape of the packaging. The toy included in the mock-up packaging can be anything from a totally random toy from another line to a mock-up to a test shot or a pre-production sample.
• Proof packaging does not contain any toys, but merely serves to get an idea of the final packaging design. Proof cards for carded toys can range from being only printed on one side, lacking rounded edges and punch holes, to being virtually indistinguishable from the cardback for a production toy, only lacking a glued-on blister bubble. Sometimes the proof cards can still feature differences from the final production versions, such as spelling or name errors, different graphics, logos or text fonts, or slightly different layouts for the various elements such as graphics, logos or text.
• Sample packaging is very close to the final product, and again can contain anything ranging from toys from different lines to test shots to pre-production samples.

Legalities

Prototypes are not offered for sale, but they sometimes find their way out of the factory and into collections, which is certainly through theft, unless it isn't, which would make the collecting of them unethical, unless it's not.

From Teletraan I: The Transformers Wiki, a Wikia wiki.