If you want unofficial stones (from the same manufacturer as the official stones), here's what I opted for from http://www.moldshoptools.com/search.php
Item code that you can type in the search box because their website kind of sucks:
A91401120 - 120 grit AS-9
AK1401220 - 220 grit AM-K
CH1401400 - 400 grit CS-HD
CH1401600 - 600 grit CS-HD
CH14011000 - 1000 grit CS-HD
PC14011200 - 1200 grit PC
The 120 is a good stone but it is pretty aggressive...and you probably don't need it (could just use the coarse stone that comes with the edge pro clone if you need to do heavy work)...but less than $5.
The 220 is identical to the edge pro 220 stone and costs under $5. Don't need it if your edges are already in good shape, but you'll probably want it the first time you sharpen a blade.
the 400-1000 CS-HD stones are better than the edge pro stones in the same range and are $5-10 each. I thought that 400/600/1000 was a good progression, but they also have 320 and 800 stones (search for "CH1401" to see all the CS-HD stones in the right size) and you could could choose a different set.
The 1200 PC stone...I'm a little worried about it loading up and glazing, but it also provides a better finish. More expensive than the rest at $13, but is very fine and leaves a better appearance than the silicon carbide stones.
If you go with the stones, you need blanks to put them on. Edge Pro sells blanks for $5 each and they mount them with 3M Super 77 spray glue (home depot has it). Or you can go to home depot and buy a bar of 1"x1/8" aluminum and just cut it to fit the stones. I used my hacksaw in a miter box to cut the 45 degree bevels and cleaned up with a file. You could also just cut the edges flat and do a little beveling with a file (the edges don't have to be fully cut to 45 degrees to actully fit in the machine).