A full suite of the very best digital darkroom products (Lightroom, Photoshop, plug-ins, HDR, panorama, and camera control) can easily set you back US$2000 or even more (plus there will be constant updates you need to keep up with that may add cost over time).
If you're balking at that, you can find some alternatives in the free and open source community that might help you out. Many of these products are built on open source or publicly available imaging engines (Enfuse, DCRaw, etc.), and they can be quite geeky to use. Still, you can pretty much duplicate everything you can get in the commercial products. Here are some of the ones I've tried and can (sometimes conditionally) recommend:
- Ingest/Transfer: gFoto (Linux, Mac)..
- Organization/Browsing/Cataloging/Viewing: digiKam (Linux, with Windows/Mac options). Alternatives: Irfanview (Windows).
- Raw Converter: DCRaw (command line). Alternatives: RPP (Mac), UFRaw (Linux), Darktable (Linux, Mac), Raw Therapee (donationware, Linux, Windows, Mac). Photivo (Linux, Windows, Mac), LightZone (Linux, Windows, Mac).
- Editing Program: Gimp (Windows, Linux, Mac).
- HDR: Luminance HDR (Linux, Windows, Mac).
- Panorama: Hugin (Linux, Windows, Mac).
- Conversion: ImageMagik (Linux, Windows, Mac). Alternatives: GraphicsMagick (Linux, Windows, Mac), Graphic Converter (shareware, Mac)
- Specialized: Deep Sky Stacker (Windows). Star Trails (Windows).