Of course there are many factors to this question. Do you already have mining equipment (e.g. a high-end GPU or a multi-GPU rig)? Have you ever mined before? It seems that Ethereum mining, for example, becomes more and more difficult, and GPU prices are still at ridiculous levels, so I personally don't think now is a good time to buy a GPU for mining. If you already have one, with the current low prices, mining difficulties can drop quite far, so you can pick up more coins than you usually could by mining, and then hold them for a price-rise later on. Of course your electricity cost comes into this too, but you need to assess your whole situation to be able to answer this question.