i don't know for sure but if i m not mistaken mining is more expensive
No this isn't true. Mining cost way more depending on the coin that you are planning to stake at, some coins require even upmost $10k value of coins in minimum to be staked, there are some that are way cheaper but not all of them cheaper than starting a mining business.
Well if we are comparing costs, staking is usually cheaper. When you mine a coin, you'd need (rough estimate) around 1,000 dollars of mining/computer equipment to make it work, this isn't even factoring the cost of electricity, which is quite a lot in some places.
Sure, staking your coins might cost more than mining in some cases, but when you stake coins, after a certain period of time you'll always get the coins back, which is unlike mining equipment which you can probably not resell for face value.
I much prefer staking.