is https://bitcoinwisdom.com/bitcoin/calculator a good place to calculate ROI? i keep messing with this thing and still cant find ROI.....everytime i do it im in the hole $700+ after 200+ days. these things need to be cheaper. and with the reliability issues of late, i think im better off just buying a bunch of btc and seeing if it increases in value over those 200 days...when stuff lasts 2 weeks and burns up or fails..... that means it is total crap!