Vitalik said 1000 ETH initially but you can join a pool with a lower amount. After sharding Close to 10 ETH. But I think individually it will be tough to get ETH from POS. ETH founders & devs holding over millions of ETH. Big exchanges holding over 100 millions of ETH, Pretty sure they will stake their ETH too and then comes the big mining pools so it will be even tough to make a fraction of ethers from staking.
I would rather join a trusted pool. it will not worth it unless you have a heavy load of eth bags.
Here I thought my few ETHs would be enough to get started on PoS network of Ethereum lol. But not in my wildest dreams I can go to anywhere near that 1000 ETH requirement lol.