Just stay away from GPU rigs for now, anything that's "
on-sale" will be a-thing-of-the-past in a few years.
I'll suggest you to pick ASICS (
SHA256^2/Bitcoin) and start mining Bitcoins in a reputable mining pool.
Do not invest in something that was made for any asic-resistant coins and new suspicious coins.
Then expand your hodlings by using those BTC to buy different Altcoins (
Make a 20-30 different coins Portfolio).
The tribal step here is to time the "
sell" at the right time, some altcoins can get a pump in a matter of months then a sudden dump in just a day.
Those 50k you have can become 500k, just buy eth and forget, check next year or 2020, it might become 2 million usd.
That's one reckless suggestion to someone who's willing to spend $50,000+ on mining rigs.