If you want to stick with easy, some of the so called "pest corals" are a great start. Especially if you will be upgrading or changing tanks when ready for some more challenging corals. These are hardy, tolerate swings and can be downright beautiful in their own right.
Kenyan trees (can get green, pink, I have even seen crazier yellowy color)
Leather toadstood (can get white or green or brownish)
Cabbage leather (cool yellow, green and pinks)
Mushrooms (discosoma easiest - red, blue, green)
Pulsing xenia
Green star polyps (I prefer Briareium over Pachyclavularia)
Then maybe zoas after you get things under control and more comfortable with maintenance, etc.
This of course is jmo from my experiences. I do not give advice on animals I have not kept.