I would not start out with an 800. The 800 has three really great things going for it.
1) super hot, finds the smallest bits of metal. But that is bad since you end up digging a lot of little small stuff you don't need.
2) the 800 can be tailored to almost any conditions. Bad side of that is it is a difficult machine to really learn.
3) it is water proof up to 3 meters. Sometimes it isn't.
Not joking have owned my 800 since march of 2018. I have experienced all of the three items I listed with my 800.
I suggest you getting back into the game with a Vanquish 540, Simplex+ or Garrett's Apex. All are state of the art, but much easier to use and very good detectors.
I own the Vanquish 540 and used to own the Simplexl+. Sold the Simplex for only one reason. The Vanquish has the same tones and TID's as my 800 and finally decided too much trouble to lean new TID's and tones with the Simplex+.