... It's why God created Google.
+1
However have 100GPU is very different between buy an ASIC.
You can mine EVERY algoritm, just switch the miner. You can also "insta-mine" lot of new coin.. We are talking about 100 GPU, lot of hashpower.
If you get stuck you can gift to your nephew or open a PC market shop
However, for calculate ROI you have to consider:
-Price that those card will value the next 1-2 years (now they are sold out everywhere, and is a quite good price)
-The possibility to "single sell" 1 GPU at time without compromise the other GPU.
-Very high scalability (you can use it for EVERYTHING, from cracking password, to project house, to earn money mining)
-Possibility of mine
quite EVERY coin born in this planet (some coin are minable only with hdd ecc)
-THE FUTURE PRICE OF THAT COIN THAT ARE YOU MINING (
)
-No more need a Christmas Tree with all of these light