These are not toy versions. The main technical difference between the Starter editions and the Professional versions are the absence of UML modelling, Class Explorer and Resource Manager tools. You also miss out on code completion for HTML, Live Code Templates, Subversion support, translation manager, refactoring and unit testing.
Not a big deal: most of these lacks are either not critical or can be addressed in other ways. Most features are the same, and you can build excellent high-performance applications with these Starter Editions.
The real restriction is the licensing:
Delphi XE Starter can be used by individuals who will earn less than US $1,000 for the applications they create with Delphi, or organizations or companies with five or fewer developers and less than US$1,000 in total annual revenue. Purchase the Professional edition or higher for larger scale commercial use.
with a similar wording for C++ Builder XE Starter.
The other question: how much? At the time of writing the Starter Editions are not in the online store, but according to this article in SD Times they will be $199 each or £149 for upgrades. Ownership of a Starter Edition gives you $100 discount if you later upgrade to a higher edition.
Delphi is as good as ever, especially bearing in mind that Microsoft has no real equivalent. Visual Studio is mostly .NET-based, whereas Delphi compiles to native code; and Visual C++ is more challenging to learn and arguably less productive. It is true that developers are waiting impatiently for 64-bit Delphi and for a promised compiler for OS X (and perhaps iOS?); but in the meantime if you need to build Windows applications do not ignore it.
Update: the European price is €199 each, or upgrades for €149.