If you build it yourself, it will likely be heavier. You must ask yourself what are you needs to find the right type of case. Will you haul it every day 5 stories high in crooked stairs? Will it travel by plane? Will it be left outside under soaking rain? Will you just put the gear in it and forget about it and leave it in a barn for 5 years? When you find the right one for your needs, the price might be just right after all...
-Roland JX3P+PG200, D50+PG1000, Juno 6+106, MKS50/70, JP8080, U220, MVS1, MDC1, MSE1, TR-707
-Korg Poly61M, M1R, MicroKorg, Micro X, Kaossilator/Pro, Monotron X3
-Yamaha DX7, TX816, TX81Z
-Future Retro 777, DSI Mopho, EMU Proteus FX