Keeping track of production costs in mixed gardens

In the interest of not reinventing the wheel...

I'm wondering if any of you have a system to keep track of cost of production for gardens with polycultures/companion planting arrangements. It doesn't seem quite as easy as keeping track of COP for monocultured beds. Any leads would be greatly appreciated. Timesheet templates especially.

I don't, but I'm sure there are some that do.  For me, I just try to get by at a reasonable cost - plant marigold seed instead of buying plants, using seed when I can (for cucumbers, squash, etc) instead of plants, but knowing when it's best to spend a bit for plants, like tomatoes...and buying them again when I plant too early!  Usually I can get a decent garden going for less than $10.  But I save seed, swap plants, etc.  And even if it cost more, I'd still do it - love playing in the dirt!