There is a Sac County Tax website,where if you know the Assessors Parcel number for the address you are interested in, you can look up previous tax information on your own.
It can be difficult to find the APN though, so often it's easiest to consult with a realtor who has access to all of this info.
Folsom Mello Roos does vary from neighborhood to neighborhood. In fact, some neighborhoods don't have it at all. So when considering the price of home you'd like to purchase you'll need to consider Mello Roos and HOAs, along with all of the normal items...property taxes, mortgage insurance, interest rate, etc.
If you have further questions, please feel to reach out to one of us directly.