One way to keep the cost down with the OMD is to use the 12-50 kit lens with the zoom gear made by an Austrian company (http://www.unterwass...-zoom-gear.html) on the Macro port 65 for the Olympus 60mm.
This will allow you to use wet lenses like the Inon UWL H100 wide angle and the Sebsee +10 or +5 diopter.
Alex mustard had a great review on a different post. you can have a look here:
With this set up you do not have to invest in extra lenses and you get the versatility of a compact camera with the incredible quality of the OMD