Time/Project Managment Software?

You could have a look at OmniPlan - see:

http://www.omnigroup.com/applications/omniplan/

It is above your $100 limit though they do offer an educational discount if that helps. Key thing is though you can download a trial version which is only limited in the number of activities you can have. You can therefore give it a good try and see if it meets you current / expected needs. The output is very professional looking and it is relatively easy to use, particularly if you are comfortable with the underlying project management principles upon which it is based.

You could also try JXProject - see:

http://www.jxproject.com/

Not quite as flexible, functional, easy to use or good looking though it is considerably cheaper at $20.

Good luck.

ConceptDraw Project-http://www.conceptdraw.com/project/

V2 is free with several Mac magazines.

Quite easy to use-a lot like MS Project.

Also take a look at Midnight Inbox and iGTD.