Hello MrConjurer,
First of all decide which generation you want to use (Genesis 3, Genesis 8 etc) I recommend either Genesis 8 or Genesis 3. Genesis 8 is the newest generation and just had its one year anniversary, which also means the next generation is about a year away since DAZ is on a 2 year generational refresh. So spend your dollars accordingly.
I recommend you purchase the PLatinum Club on the DAZ site, with this you get much better discounts on new DAZ originals, plus they have Platinum plus marked items that are in the $3-$6 range and these are many times very useful items, plus they have weekly freebies which are also usually very good.
As for genitalia, you have to purchase the Pro bundle of any core model you use, for instance by purchasing Victoria 8 pro bundle you would get the stock DAZ genitals (called anatomical elements on that site) with basic morphs. But a better way to go is to get the base model (once you get platinum club) then come here to renderotica for your pick of superior genitalia. For females, there is New Gens by 3Feetwolf, Golden Palace by Meipe (the one I use) and morph packs for the stock DAZ Anatomical Elements. For males, there is Dicktator by Meipe (the one I use), TAB by Erogenesis, and OMGDICK by Sledgehammer plus various morph sets for the stock DAZ Anatomical Elements.
If you can afford them get them all and try them to see what works best for you, or read these forums and read on which seems more intuitive for you.
Going back to the DAZ site, once you decide which generation you need the base morphs sold separately, there are head and face morph sets, body morphs and recently expressions too. There are also some good morphs sold by a vendor names Zev0 who sells great morph packs called breast control, glute control etc, which do what the title says.
Before you start animating, and I am sorry I do not know your background, but start playing with simple single frame stills first and learn posing, there are many pose packs out there but you need to learn to do it yourself, and focus on lighting and camera work too.
Finally learn how to use the tabs in DAZ, particularly the Surface tab, this is where you can change the surface of anything to anything. But all the tabs are important, master as much of them as you can.