Covering the modern era of the classic Colorforms Space Aliens action figures. Presented in association with 16bit.com. Not an official site. Visit TheOuterSpaceMen.com for more.
Action Figure Xpress has sets of all 4 Outer Space Men for $47.99. Given that they're pretty limited, the price isn't half bad. Closed auctions on eBay have been $50-$75 for the set, or about $17-$20 for a single figure. Or, of course, you could just order the normal figure set which is due to ship later this year. The set is limited to roughly 300.
If you didn't get to New York Comic-Con, odds are you ordered (or tried to order) the four Beta Wave Outer Space Men figures from Store Horsemen. If you did, your order has been processed and odds are you have just received a FedEx shipping notification that your order is being processed for shipment today.
After months of hoping and an unprecedented two waves of "prepaints," Store Horsemen added the first four figures for sale. Right now. 
If you collected or read about the original Colorforms Outer Space Men toys, one thing you might remember is that packaged samples of toys that never got made are a big part of it. Thankfully, these new packaged samples of the first four figures are really, honestly coming. They go on sale tomorrow night!
After months of pre-paints and rumors, the first look at the final production figures and word on pre-orders are up on the Four Horsemen web site. Figures will be available in pairs for $22 or as a set of four for $40, plus shipping. It's also worth noting that the final painted figures look really good-- considering the asking price and the likely low production run, we're quite impressed.
A few minutes late, but still timely, Store Horsemen has the 4 New York Comic-Con Outer Space Men up for pre-order. Only 30 sets are available and it's limited to 1 per person. A set is $40 and $9 for domestic shipping in the United States. Good luck!
UPDATE #1: These have since sold out-- by about 6:10 PM.
UPDATE #2: On The Forums, the Four Horsemen confirmed the set sold through in 1 minute, 41 seconds. If your order confirmation number ends in 2998 or less, you got in. If not, odds are your order will be canceled. Obviously, watch their forums for more specifics on this issue. And hope they make more to fill the orders with next time.
