Rosco or Lee filters about $8.00 a sheet and those sheets are 17x22. Try not to shoot through the scratched parts.
If you are really lucky, you might find a theater supply shop that also does contract lighting and might have a bunch of scraps around that you could have for free.
These gels are not perfect, but should give you an idea of what colors you need. Get a Rosco or Lee filter swatch book and see what you can cross reference to real photo quality filters before obtaining any gels.