Floor Coverings - Ahh Yeah!

[CoventryCat86]

As long as your coin is well-affixed to the subfloor, you could splash a couple coats of poly on it and be good to go. I'd hate to try to clean the filth in all the cracks between the pennies, but you could do it on the cheap.

Just sayin'

No, you're NOT going to "be good to go" by "splash(ing) a couple of coats of poly on it" and end up with a result that is acceptable for anything other than a tree fort. This would be totally unacceptable to what the author of this thread is looking to do which is for ideas for a KITCHEN FLOOR (talk about the highest traffic area in any house other than a tree fort) in an old house that he's renovating for his use and probably trying to add value to his home for future resale as opposed to the tree fort which kids will lose interest in next year.

If you want to "do it on the cheap" you could put down carpeting too like George suggested or hell, just leave 3/4" CDX sub floor! Both of those alternatives are better than just gluing down pennies and splashing a couple of coat of MinWax on it.