Ok, I did a little research on this.
I found the same casting resin on this
eBay auction
Total Cost for 2 Quarts (mixed): $40.00 shipped
And I found some magnets at
Magnets4Less (Note that these are narrower then the ones used in the DIY guide, but I believe they will still work.
Total Cost for 12 magnets: $53.49 shipped
This would provide enough material to make 6 PAIRS (a pair being equivalent to a magfloat).
Total cost per pair: $15.60
Fosters & Smith has the large MagFloats on sale for $15.00, but this does not include shipping.
I'm in for 2 or 3 pairs if someone else wants to go in on the materials with me (please double check my math and my estimation that the smaller magnets would still do the trick).
-JB