Here is a cheap solution if you want a straight light flare, like the one an anamorphic lens gives, you will be needing a fishing line, permanent markers ( if you want a colored flare), and a way to hold this in front of the lens (for this i used a third party cokin P filter holder, the cheapeast one i could find on ebay)

The only technical consideration is that the fishing line is spaced by 0.5 cm, because that is the spacing that i discover works best on a Canon fd 50mm 1.4., from f1.4 to f8.

Some pics:

And a video of the DIY filter: