Structural foam still requires an injection molder and hard tooling. So, if you plan to make thousands of them, it might be the way to go. Perhaps multi-cavity tooling. You are probably looking at $100,000.00 to get started. And foam molding comes with it's own set of processing problems. I've done it in the past, but it can be tricky.
You might consider a contract manufacturer. You buy the tool and pay him so much per part to mold them.
There's also rapid prototyping to look into.
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