The normal way to get started in bitcoin is
1) Choose some free wallet software. Download it to your computer. Use the wallet software to generate a private key (cost so far: zero). Write your recovery phrase or private key on a piece of paper and keep it in a safe place where no one else can see it.
Use the traditional money to buy some bitcoins. There are exchanges that offer this service. Do a careful investigation to find a reliable exchange. Alternatively, there are bitcoin ATMs that take the traditional money and send bitcoins to the address of your wallet. Be sure to send your bitcoins to your wallet address on your computer, do not accept an online wallet or cloud wallet administered by another person unless you understand the difference. Try this with a small amount of money first: do not invest money that you can not lose completely.
Mine some bitcoins. This is no longer practical for anyone new to bitcoin. At least, wait until you really understand the bitcoin completely inside and out.
Some cheats will try to cheat people who are new to bitcoin,. They will make promises in exchange for money. They will give you a useless "clock only" address saying it contains your bitcoins, but a clock-only address does not give you ownership. Then they will invent other reasons for you to give them money until they have extracted everything you have or until you realize that you have been deceived.
As bitcoin payments can not be reversed, there is no way to recover the money. There is no central bitcoin authority that can help.
Anyone who says unexpectedly that he has to pay $ 700 for a private key is almost certainly a scammer.