It depends on which one you want. There are types of crypto exchanges. Like the noncustododial exchanges, the instant exchanges and the custodial exchanges.
Pardon! I beg to differ, this is wrong. We have just centralized and decentralized exchanges, custodial and noncustodial have to do with custody of your wallet when you manage your private keys or when a third party manage them for you.
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You see, forget about the commissions, the bonuses, the sweet talk thing about centralized exchanges. Let's start from your capital, You have just $50 to start with as a beginner, how do you intend to enjoy benefits with such a fund? it is very little to enjoy all the sweet rose promises centralized exchanges will want to offer you.
Let's come back to your security and privacy concerns, I have a small token of advice to share with you, don't do KYC on any changes, don't submit your precious passports and ID cards to anyone, once you give them out, you just handed over the most valuable thing you can never get back again, what happens to future of that documents depends on how they use it and it will bounce back to you.
Use exchanges that don't request for mandatory KYC before you could trade and withdraw your coins, Kucoin exchange is a good start, Good luck!