Miner has a fixed cost. You buy it once and it is yours forever. As you mine daily, you recover the cost of the miner and move into profit. The price of the miner and the coin that you are mining will determine how fast you will be able to recoup the cost.
But there is one additional cost that is variable monthly. This is the power cost. Now if you are using one miner in your home then this isn’t something you really need to worry about. However, it is important that you make sure you are aware of the power output 110 vs 220. If a power conversion is required, it is squarely your responsibility to ensure you have your ducks in a row. It is not advised that you find workarounds. You should never EVER play with electricity based on DIY tips. Follow the manufacturer’s guidelines and/or hire an electrician.
If you are creating your own farm i.e. deploying multiple miners and dedicating a room to them, you should be aware that your power bill will reflect this change. To put this into perspective, you’re looking at a power cost of $173 per one Bitcoin transaction in the USA. Another factor to take into consideration is that miners generate heat. To combat that, you will need to run cooling systems around the clock.
If you are using just one or two miners at home, it is likely you won’t be able to see that difference in your bill at all.