I'm building a little toy, and need to read a hand-encoded storage medium something like punched tape. Right now I'm looking at the Panasonic CNB1002 reflective photosensors, which integrate an IR LED and phototransistor in a small gull-wing SMD package. In my small quantities they're about $0.55 each. I need three - a clock bit, and two data channels. Apart from the cost they're perfect - they read back well at a distance up to about 0.5mm (claimed 1mm, but my materials aren't ideal).
Is there a cheaper alternative? Discrete LEDs and phototransistors seem to be even more expensive.
I looked at CdS cells but they're also expensive-ish, and also don't respond fast enough - I want to read 256 clocks in a 1-second run, and that means about 1.5ms response time or better. Plus the varieties I've found are not well shaped for the application, as I only have one mounting surface for the illuminator and reader (but I'd be happy to be pointed at other flavors of cell, since I was fighting Digi-Key's search engine.