In general, there are two ways to acquire bitcoins: buying them with real money or "mining" them. The process of mining is the process of acquiring bitcoin, and therefore mining is mining for coins.
Well there are other ways to earn bitcoin and participating signature campaign is one of the ways to earn bitcoin and mining bitcoin isn't an easy one and considering the cost of acquiring mining machines and cost of setting up the miner is something else and if you have the money to start up a mining farm then I will advice that you just use the money to buy bitcoin and hold for longer time because it has been proven that buying and holding bitcoin for a long time is the best and with minimal least.
But if you have the option of buying and mining, I will always advice that you go for buying if the money is big or equivalent to starting a mining farm.