It is not necessary to purchase dedicated IP for small scale and basic website, you can use a shared IP for it.
Class C Ip address can be dedicated or shared. If there is only a single website under the IP then it can be considered as a dedicated Ip for it.
Class C IP addresses range from 192.0.0.x to 223.255.255.x. The default subnet mask for Class C is 255.255.255.x.
Class C gives 2097152 (221) Network addresses and 254 (28-2) Host addresses.
IP Address (Internet Protocol Address) is a unique address that computing devices such as personal computers, tablets, and smartphones use to identify itself and communicate with other devices in the IP network. Any device connected to the IP network must have a unique IP address within the network. An IP address is analogous to a street address or telephone number in that it is used to uniquely identify an entity.
The dedicated IP is used for website if you need the website to run on the IP address which is other than the shared IP address. If there is SSL then it is used to installed on the dedicated IP.
It does not mean that the website will run from the other server, it will run from the same server , the IP will from the range of the IP address of shared hosting server.
Class identifies the range of your IP address and the default subnet mask.
A class - 0 to 127 with default mask of 255.0.0.0
B class - 128 to 191 with default mask of 255.255.0.0
C class - 192 to 223 with default mask of 255.255.255.0
D class - 224 to 247 (not currently used)
E class - 248 to 255 (not currently used)
Understanding the differenc classes of IP addresses is better done if you take a networking course of some kind.
As for the SSL certificate and dedicated IP, its always best to have a dedicated IP on a server, cPanel even offers free SSL certificates, or you can get it with letsencrypt if y you dont want the cost of it.