It really depends on what you're wanting to make.
DAZ usually has some good deals, especially to the Platinum Club members (basically $100/year or $8/month +$30 startup, whatever works for you.)
When you first download the program it has a starter content pack and some tutorials to get you started, which if I recall comes with the base female model Victoria 4. Though I recommend buying the additional morph package so you can further customize the models to your liking.
A lot of content obviously costs money, not only from DAZ's corporate offices, but artists also make their own content (which is something I eventually want to do). Hit me up on Xfire or PM me and I'll link you up to some freebie stuff to work with.