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.
Give us more details.
Luck comes and goes. Skill is forever. The supply of fools will always outstrip the demand .