Square 1s are not available in stores anymore because of the bankrupcy of Irwin Toys on the toy. The only way to get these puzzles are from EBay or any other Auctioning Site. Try searching Super Cubix or Cube-21 for possibly cheaper prices... Trust me my friends got me a square one for 45 dollars when they probably would have paid 20 maximum looking for a super cubix or cube 21.
As for Megaminxs, tiled versions can be purchased on Mefferts. http://sites.webec.com.hk/meffert/index ... &product=4
Stickered version originals can be purchased on EBay but tiles are ok on this puzzle, At least one doesnt have to worry about fading stickers.