Get a DV deck. Turn on the display information, this will include timecode. Dub it to VHS with that display info.
Not really low cost unless you already have the deck. But since you don’t have FCP, I doubt that you do.
This is really the wrong forum to ask this question, as we all use FCP, and you’ll be hard pressed to find one person here who uses iMovie.
Try the Apple Discussions. There is an iMovie one…