I purchased a Samsun 960 EVO m.2 250GB and although is not like I can´t purchase a second SSD that is not actually on my anytime soon plans! Since the second VM will be used for mostly watch movies and play League of Legends I don't think I would ever worry about an SSD for it.
About the storage part, I need to keep it budget for now! For the information provided, I think that I will:
1- Install the SSD as the main drive for the main VM.
2- Install a spare 2.5 old HDD from a laptop I got broken on the closet for the second VM.
3- Install a 200 GB 7200 RPM 64 drive as a cache drive that as well got in the closet.
4- Use my 2 TB 7200 RPM 64 cache drive as storage for both VM´s.
I need to purchase 2 monitors, 16gm more RAM, and a better cooling system since I´m using the stock one since the AIO solution I had gone wrong. After that, I might consider the purchase of more SSD drives.
In my opinion, I think this will be the best I can do at the moment for the setup. I really appreciate all the help! If there's any further recommendation I'll be glad to hear it.