Actually, it's way more than $100. Natchez has Pro 1000 kit with dies for $160 and it comes with case feeder.
Scheels/Graf has Dillon 550B for around $390 and a set of Dillon dies for $66 and you still don't have a case feeder. If you load multiple calibers, you also need to factor in caliber change costs. And Dillon 550 don't have auto index like the Pro 1000, you will need Dillon 650 for auto index.
I agree that over time, even the cost difference for 650 with case feeder and caliber changes can be justified but some reloaders may not want to or be able to spend $700 - $1200+ on a progressive set up. For them, Pro 1000 offers another progressive option that is initially affordable (Keep in mind that some of us were/are starving students/young adults who still want to shoot a lot
).
Is Pro 1000 option for everyone? No. Is it viable for some? Probably and I wonder just how many thousands of Pro 1000 owners successfully reload on them all across the nation every month?
For me, I have become spoiled by the convenience of 3 dedicated Pro 1000 set ups for 9mm, 40S&W and 45ACP all with case feeders and my entire set up costed less than a single caliber Dillon 650 set up without the case feeder.
I have considered replacing/adding the Dillon/Hornady progressive press but when my wife asks me, "But honey, will they load more accurate ammo?" I have to ponder and tell her no.