I disagree with the advice of starting with a single stage press. If she is planning to load mainly pistol cartridges in volume, she will hate loading on a single stage. A progressive press is indeed more complicated, but it's just a machine and any reasonably-intelligent person can learn to properly operate one pretty easily. I started loading on a 550B, and I've never found any purpose at all for owning a single stage press. I've had a couple and still have one in a cabinet somewhere, but every time I've set them up I've quickly realized that they don't do anything better than the 550, they just do it a lot slower.
I've got the 550 and also a 650, and for a first press I'd recommend the 550. If I could only have one press it'd be the 550. It can crank out bulk ammo pretty fast, and has a lot fewer parts to maintain and service. With a few minor tweaks, it will also work great for match grade rifle ammo. It's a heck of a lot cheaper than a 650/750, if that's a concern. I use the 650 mainly for bulk pistol stuff, and also as a really expensive de-primer for rifle cartridges. It's ok, but it seems like I am always needing to fix something on it whereas the 550 just keeps on going without issue.
Good luck.