A: To have fun. Just try some random number(can be a really big number too) and if you are very very VERY lucky, maybe you can find some free bitcoin or sats sitting in those addresses.

A: Sure. Just generate a transaction with required information(from, to, amount, fee), sign and send it to bitcoin network.

A: NO. Never neither enter nor keep your private key, secret or 24 word seeds online. Use a cold wallet.

A: NO. Never use those addresses for your transactions. To receive bitcoin, always generate new addresses from seed words/cold wallet.

A: A random number(private key) between 1 and 2²⁵⁶ is used in an elliptic curve multiplication, a one-way cryptographic function, to generate a public key. From the public, we use a one-way cryptographic hash function to generate a bitcoin address.(from the book "Mastering Bitcoin")

A: To show that altough anyone can try to find some free bitcoin, it is almost impossible to find some.

A: Because there are so many legacy bitcoin addresses to look for. To be exact, the are 115792089237316195423570985008687907853269984665640564039457584007908834673617 legacy addresses to check.

A: Yes, try the numbers between 1 and 10 as a secret and you'll see it for yourself in received section.

A: Yes it is 10 for now. After 10 trials you should wait for 60 minutes.

A: I will add the pro version functionality if there is a demand for it. So if you want that, notify me via hello@findfreebitcoin.com