Corals for beginners:
Corallimorphs - Fantastic for beginners and experienced people. Lots of colours, very tough and easy to frag.
Zoanthids - Same as Corallimorphs really.
Xenia - Can be nice (Pulsing Xenia) but can sometimes become a pest.
Those are nice to start off. Once you get into the swing of things you can go for some LPS
As for the Calcium etc let it be known, I have never dosed anything supplemental into my aquarium and have seen tons of growth. I had two Macro Algaes literally grow out of a piece of LR
. (I'll post pics you want). They are truely beautiful and grow like crazy. I've trimmed them numerous times and they grow back. This is with dosing nothing. I've also had a Hitchhiker Crab that has shed it's skin 7 times since I first noticed it (3 months ago). My corals had all shown fantastic growth until I sadly lost them in a recent hot day when I wasn't home. (My Corallimorphs all survived as a testament to their hardiness)
Also my Anenome survived the hot day and is still going strong after recovering.
So personally, I would never dose anything into my aquarium, but that stuff may help. I like to let the coralline algae grow naturally, it helps tell me there is enough Calcium in the water.