It's too late to get any profit from mining. I wouldn't buy a new computer to mine. I think z cash cannot be mined with a ASIC but works well with GPU. I never tried mining smartcash. I mined some with CPU almost two years ago but it is not worth buying a new computer just for mining. You buy a GPU unit to attach. It won't be expensive. There is some cool stuff cheap on Aliexpress that delivers free to Korea.