Design 3D Printable Relief Moulds

I need seven master mould boxes modelled so I can print them and use them to create silicone cavity moulds for casting plaster miniatures. Each box will house four different flat-backed figures, giving a total of twenty-eight unique relief designs... (Budget: $250 - $750 AUD, Jobs: 3D CAD, 3D Design, 3D Drafting, 3D Modelling, 3D Print Design, 3D Printing, 3D Rendering, CAD / SolidWorks, CAD/CAM, Solidworks)