Your best option before you invest money in a 3D printer or laser cutter would be to try some designs and have these manufactured by others first. You can run your own 3D prints through Shapeways without necessarily putting them up for sale (although this might prove expensive given the Shapeways handling and shipping charges) or a local 3D print service (definitely likely to be cheaper, although the quality may vary). Similarly, this can be done with laser cut designs and local manufacturers who are likely to be able to produce larger sheets/designs (up to 2400 mm or 1200 mm x 600 mm) than on anything which you could reasonably produce at home (without significant expense).
For 3D design software, there is a range of options, but that with probably the most shallow learning curve would be TinkerCAD (as its' focus is primarily educational) and for laser cutting, any SVG or vector design package would suffice (I have used Inkscape)