monero? people say about this coin all the time when they need anonymous transaction. I'm still dont understand how monero can hide their transaction. should I buy some to test
Simple. It is achieved with 4 things:
1. Ring signatures, that hide the output being used by hiding it among several others that also appear to be used. NOTE: this is very different than mixing.
2. Stealth addresses, that removes the association between outputs and addresses.
3. RingCT, that is basically a confidential transactions that works with a ring signatures. (Updated with Bulletproofs in 2018)
4. Kovri, that hides the IP for the transaction broadcast. This data is never stored on-chain, but it can help protect users from malicious nodes. ( Updated in 2018)
But even with all that Monero is still work in progress and research and adds new innovations to always stray ahead of blockchain analysis.
You dont need to buy any Monero. Download GUI
https://github.com/monero-project/monero-gui/releases/tag/v0.11.1.0 and set to testnet and solo mine yourself few testnet Monero and play wit them.