in walmarts the other day, I noticed pool noodles marked down to 25�. It struck me that this might be a suitable crappie condo material. any thoughts?

Sinking foam is probably a bad idea. I think it would deteriorate, disconnect, and become litter. Seems like it would be a hook clinger too.

All you would do is stay hung up. Not to mention it would take a lot of weight to sink them.

I think that's not a great Idea, I would say pvc or just brush would be the way to go

Not a good idea. You want something that doesn't float well. Easiest thing I have found is to cut a green bush, small tree or large branch. Take it to your chosen location and depth. LOCATION is the most important thing. Zip tie a cinder block or sand bag to it and slide it over the side.
By using green brush, the wood is still full of moisture and not very buoyant. Old dried brush tends to float and you need many blocks to sink. Pool noodles would be worse. I like cedar trees or large oak branches. Cost per brush pile is under $3. I have only been at this a couple of years, but this is what works best for me. Don't over complicate it.