I bought a gently used 550b several years ago with literally all the extras. A guy was simply going a different way and sold everything he had. Too much to list really. I sold extra dies, caliber conversions, powder dispensers, tool holders and bullets, electronic scale and recouped 90% of the price. Kept everything for 9mm and .223 then bought my .308 stuff. Great customer service from Dillon for sure that got me started. Nice thing also is just about anything Dillon sells very quickly on online auction services. It was an outstanding deal ....
Look at the set-up carefully, download an owners manual if possible and give the unit a good once over before you buy. My bet is you'll do well.
Scott