Got rocks?

I don't have rocks so I'm planning on making sandbags from scrap material I'm getting from work to hold down my cardboard mulch. Then, during the summer, I'm going to pile grass clippings on it as they occur.

I have rocks, but I don't believe they're big enough for this. I'd also need quite a few as it's a very sizeable amount of cardboard I'm thinking about putting down. I wish the fabric stakes would work, but given they couldn't even keep the fabric down, I can't see them working with the cardboard (we do get some really strong winds from time to time).

Use soil then, or if it is too clumpy, compost, which may be too expensive. That's why we use wood chips: free and lasting, they suppress weeds also in year two (and three), preserve water, protect roots, and improve the soil.

Free isn't a word I associate with wood chips around here (Utah). If it were, I'd use them. I've got a roughly 10,000 sqft garden I'm trying to keep weeds out of. I've found an alternative for about half of it, but it's not a good fit for the rest.
I put some ground up wood chips in my chicken pen about a year back and I like what the chickens have done with it. The area I'm trying to focus on with the cardboard is footpaths. I'll confess I'm not real interested in improving that soil because weeds would just grow in it. If I were rich, I'd concrete it. I already employ micro irrigation to make sure it gets no water, but even without water some of the weeds manage to thrive anyway.