Well then I read that the best bet would be to upgrade my camera so that I can purchase cheaper lenses....
Don't believe everything you read, because I don't think what you read told the whole story.
Nikon makes
AF-S designated lenses that have a focus motor in them and all current Nikon bodies use that in-the-lens motor to focus with, even if there is an auto focus motor in the camera body.
Nikon also still offers some new
AF designated lenses that don't have a focus motor (no -S). Most of them are MUCH MORE EXPENSIVE than the AF-S entry-level version of an equivelent lens.
Nikon currently offers a $200
AF-S 35 mm f/1.8G lens, a $390
AF f/2 D lens, and a $1165 NIKKOR 35 mm f/1.4
manual focus only lens. Which would you likely buy?
The lens maximum aperture has more to do with what a lens costs, than if the lens has a focus motor in it or not.
Nikon also made lens years ago that not only won't auto focus on any Nikon DSLR made today, they won't meter either. Some of them will auto focus but won't meter.
I recommend you stick with the D3000 and the AF-S lenses you can afford.
But if you want, here is the Nikon Budget Zoom Lens Trinity:
First is an AF-S lens that has a focus motor in it and the other 2 are AF and don't have a focus motor in them;
Nikon 12-24mm f/4G ED IF Autofocus DX Nikkor Zoom Lens
Nikon 24-85mm f/2.8-4.0D IF AF Zoom Nikkor Lens for Nikon Digital SLR Cameras
Nikon 80-200mm f/2.8D ED AF Zoom Nikkor Lens for Nikon Digital SLR Cameras
As you can see the 2 AF (no focus motor in them) ae not inexpensive. Good glass costs a lot of money.
Nikon currently offers 76 lenses, most of them AF-S lenses
http://www.nikonusa.com/Nikon-Products/Camera-Lenses/All-Lenses/index.page and the AF lenses are slowly being replaced by new AF-S lenses. Eventually, Nikon will eliminate the auto focus motor form all of their camera bodies, just like Canon did in one huge fell swoop back in 1987. At least Nikon is doing it gradually.
Only 21 of the current lineup are
AF lenses and many of them are specialty lenses you won't be interested in. A few more of the 76 choices are
manual focus only.