People staking with 1 million EMC has reported to get 1 stake on average within 2 day. That's what I have seen in the discord channel. However, only having a lot of coins don't necessarily mean you will get a lot of stakes. You need to have splited them perfectly, coins age must be older, you need to have the best strategy to get the best output. When I used to get 2 blocks a day, someone with same or even low amount of coins have reported that he used to get 4 blocks a day. So, there are some factors you need to examine, experiment and after that, you will know what's the best strategy work for you.
If you want a good amount of EMC to start staking, I would recommend 5 million which would cost you around 0.10 BTC or $3500 maximum as people who got the early airdrop are dumping now.