Here are the tools I used for my Ludum Dare entry (with links). All of them are FREE to use.
I hope you find this helpful :)

GIMP for Graphics

- Photoshop Sketching brushes by Wootha (used with "Pen Generic" brush dynamic) - Iwarp plugin (comes with GIMP) for quick animations - Script to export layers as spritesheet

Stencyl for Code/Scripting

- download free at Stencyl.com & export for free to Flash/HTML5, pay 100$/year if you want to publish to Desktop - easy to use, but not very performant for bigger scenes - cross-platform editor (used it under Linux Mint)

Etc

• Sony Alpha 58 (~400€) with 18-55mm kit lens to take background photo

• Musician used older keyboard for music, we recorded it live with a cheap sound recorder & RODE mic

• Audacity to cut & level sounds (free), Sound Converter (Linux only) to quickly convert to needed format for Stencyl

• tomato.es for timetracking/taking regular breaks
• Chronolapse to record timelapse, FFMPEG to convert to video and combine with music

I hope this was useful!

Click here to play my game

(and leave me a comment please :))