Transaction fees and trading commissions will eat up your entire balance. Its really not worth it for small purchases.
Do you know what coinbase will charge me?
Check these links from Coinbase:
Coinbase pricing and fees disclosuresExchange fees
I can relate to OP and understand him. It's difficult for him to learn something that he doesn't own at first, but it's more difficult to lose money without knowing anything. That's why it's better to know first like some basics.
I'm glad you are here OP and asked some questions.
Expect that most of us don't recommend using centralized exchange but sometimes it depends on your purpose, let's say you can buy Bitcoin in a centralized exchange then just withdraw it to your personal Bitcoin wallet, which is better. (So from here, you need also to learn what a Bitcoin wallet and what are the types of Bitcoin wallet)