If you shot colour neg, it's huge latitude probably covered up your metered finder's inaccuracy. E6 film has very little latitude relative to C-41 and showed up the metered finder's problems. Frankly, since film and processing aren't getting any cheaper, I'd look into a handheld meter. Older Sekonics like the 328 or the newer(and still current)308 will do incident and flash metering. Older Minolta Autometers like the IV are another option but might be a bit pricier.<$100 is a tall order unless you can find an old Polaris meter.