At it's current price I would advise buying over trying to mine it if you don't already have the hardware. Of course I'm not giving investment advice or anything, but with the custom sia ASIC miners being made, the GPU mining of siacoin has its days numbered.
I guess the part about buying instead of mining goes for most cryptocurrency right now too though. The only exception would be Monero, or any cryptonight based coin really. That algorithm can be mined with old junker graphic cards and still get a decent hashrate, and CPU's too.