That rcbs package is an excellent place to start. There's a lot of items in that package that you'll use/need even if you pick up 2 or 3 different dillons.

A good single stage press is the foundation for any reloader. Things like test loads and precision ammo for target pistols/rifles are best done on a single stage press. Anything to do with bullet manipulation needs a single stage press, doesn't matter if it's swaging bullets, bump dies for bullets, push thru sizing dies for bullets, bullet pullers, etc.