It is possible to give the following most comprehensible explanation to the foregoing concept:
The above classification is used for the registration of TM. And speaking directly about the classes themselves, prominent basis is the "Principle of homogeneity of goods and services," followed by systematization in selection. Further, it is possible to include simplification of the compilation of applications for the registration of TM directly by the applicants.
On this page, at the bottom, you can see the tables of classes according to the ICGS (these is the list of classes). As for the link between the value of TM and the number of required classes, the price depends on how many of these classes you plan to open.
The more classes, the more voluminous will be the amount of state fee, required to be paid.
The international classification of goods and services is an obligatory stage in the registration of trademarks.
If necessary, and more importantly - if appropriate, you will be able to register your TM immediately for all classes of the ICGS.
All of your questions can be answered by specialists of law firm Law&Trust International. Consultations are possible both remotely and during personal meeting with the lawyer.