Meditation cushions are a very personal fit. Suggest seeing if you can try some at a retail store, meditation centre, or try a few from Amazon if you are happy with the return shipping costs. They should be relatively comfortable from the beginning and will become more so as you practice more with them.

I presently use an inflatable one when I travel (on my 3rd in 8 years, it keeps developing leaks) and a Cosmic Cushion with buckwheat as my usual cushion.

Some people like kapok filling, I prefer buckwheat. Agreed with the zabuton suggestion.