these digital converters are exactly cheap, or certainily not as cheap as free vcrs on craigslist. Can a older vcr be used as a digital to analog converter?

All converter boxes already have converters built in. Channel 3 or 4 output. As long as the VCR has audio/video inputs then you should be good.

I'm not sure what you're asking?
Can you use an old VCR to tune Digital stations? No, they have analog tuners.

Can you use them to hook a DVD player to an older TV, maybe, they can be used for r.f. conversion but you may have problems with Macrovision screwing with the signal.