If you are talking cloud mining cost can be very substantial. As an example I will be using a site like eobot. You could possibly get enough hash for about 420 BTC to get 1.3 bitcoin a day maybe. And you can see it would take 323 days just to get an ROI. but you shoudl have that hash for another 1497 days after your ROI. Thuis giving you a complete profit of
1946 BTC in a 5 year investment. ( these calculations did not incorporate difficulty rises or reward cuts)

If you are renting hardware for 24 hours to hit a block you will need a minimum of 4 PHS of power for 24 hours and hope to hit a block (which is not guaranteed) you would have to spend 60 BTC in order to try this so you would pray you hit 3 or 4 blocks (which COULD happen) in 24 hours to even make your money back. then if your renting hash you will need your own site and your own pool for personal use only. Renting hash and mining in a pool is absolutely NOT profitable in any way. Well maybe if triplemining would pay it out it would be worth it to rent all that hash and point it to triple mining, But i wonder if someone actually did that if they would even be able to pay that member what they really earned. Other than that you would need to have your own site and pool to solomine for yourself.

If you are talking your own equipment again you will want 3+ PHS of power, a stand alone building set up with the correct heat exhaust and cold air intake dehumidifier and solar energy. with that much power consumption the solar power alone could cost in the hundreds of thousands not to mention the equipment purchases. if we use S4s we can get an s4 right now for about 1400 dollars shipped. thats 2 THS using 1300 watts of power you will need a minimum of 1500 machines to get 3 PHS. So start up you are looking well into the millions of dollars in startup costs with no or very little overhead once completed. If you do this plan you will have no electric costs and 3 PHS of power that could actually bring in over 50 BTC a day with enough luck right now.

For just 1 BTC a day average you may want a minimum of 500 Thash and solar to power them and if your lucky you will solve enough blocks in a month to equal 1 BTC or more a day average.

HOWEVER you were so very broad in your question to honestly answer this question, you can buy 1 single 1 THSmachine for 500 bucks right now spend the 33 dollars a month to run the machine and "POSSIBLY" solve a block in 8 months so if this were the case you would have 764 dollars invested. and it would depend on the value of bitcoins at the time you solved the block as to how much you would make, if you solved the block and the rates were 370 like now your reward would be 9250 dollars for a profit of 8486 in 8 months. ( this is a very VERY best case scenario with lots of luck and would involve the capitol to pay for the equipment and its electric costs for the 8 months it runs.)