Freeware basic particle generator...
I recently downloaded a small program called Explogenv2 that allows you to create explosions for games, while looking at it and messing around with the settings I saw some potential for creating basic particle effects. It has 3 inbuilt emitters but I just used number 1 and created a series of still images to create an animation. You can find it at:
http://www.kenginegaming.com/explogen2page.php
It will create your file but you will need another small app called Img2Avi, where you can import a set of bitmap images and it will convert them to a .avi file that can then be opened in all the popular editors. It can be found at:
Img2Avi Jpg2Avi Bmp2Avi Gif2Avi
Unfortunately the .avi files created don't have an alpha channel but I just used Luma Keying to get rid of the black background.
If you decide to download Explogenv2, try these settings to create a particle effect:
Explosion 1 (on) Explosions 2 and 3 set to off
Speed 1
Amount 400
Life 30
Particles
Speed 4
Amount 40
Life 30
Type Fuzzy
Start Colour Purple R=128 G=128 B=255
End Colour Light Grey R=192 G=192 B=192