As far as price, and care level- you could start with leathers, mushrooms and other soft corals. Once you feel comfortable with those you could start with some LPS
corals. You will need to upgrade lights though for more difficult corals.
Temp needs to be between 72-78. Alk
needs to be between 8 and 12. Calcium needs to be in the range of 420-460 area. You will need to start using reef salt mixes. PH should be at 8.3 or as close as possible. Salinity should be between 1.023 and 1.025.
Is this an already established tank?