Why not use the money to get each of your future kids a hope chest? It's a basic kind of thing that can be repurposed in many ways, isn't so huge that taking it while moving will be an issue, and it won't be hard to find or make one with quality wood.

Use the Sagulator

GrainWood Furniture. The IKEA/Wayfair flatpack assemble-it-yourself concept, but made out of solid wood. Prices aren't crazy.

You could also build a bed frame with relatively basic tools and dimensional lumber. Rockler woodworking has brackets like these that don't require mortises.

Today you enter the club