You might have heard it right, but whoever said it was very wrong.  There are a ton of threads comparing and contrasting cloud mining services.  CEX consistently comes out as the most expensive, least value for your investment.

You need to realize that to earn a steady income mining means constantly reinvesting in new hardware (or purchasing more GH/s in cloud mining) to maintain your income level.  The two biggest factors involved are changing difficulty in mining the coins and value of BTC to fiat.  If you look at historical charts, you can see that the difficulty has been growing at a very fast rate, yet the price of BTC has not moved very much at all.

So, looking at numbers, as of right now BTC is just about $375.  This falls into your income range.  To mine 1BTC a month means you need to have 2.32TH/s of hashing power.  Again, this is based on numbers right now, and absolutely will change.  In fact, in about 6.5 days from now, the difficulty will change.  During this time, the value of BTC may also change.

I definitely suggest you take a look at some of the cloud mining posts and do some more research into whether or not mining is going to be a worthwhile investment for you.