Can anyone tell me the breakdown of costs incurred should I decide to issue my custom token on Stellar?
There are the base fees on stellar, which are almost nothing. You need to plan on having an issuing account, a distribution account and maybe a warm reserve account. With trustlines, etc. about 8-10 XLM goes a long way.
The real cost is all the rest. You will need a domain + stellar.toml hosted somewhere with https. So, you have to consider the hosting cost for that as well.