Waves 5 and 6 of Outer Space Men will go up for sale this Sunday and if history is any indication, the 9 PM EST launch is a good guesstimate - expect they'll be up by Monday morning. The set is a fairly reasonable $50. (For the record, the Alpha Phase and Galactic Holiday Phase were $50 each, while the Beta Phase was $65.) Figures are expected to ship in late March.
After this wave, only 2 original OSM figures remain to be released (Gamma X and Colossus Rex will likely be starting as SDCC exclusives in July) with a few new characters like Jack Asteroid and Terra Firma expected to join them.