If I was looking for a lower cost alternative I would consider feeding half of a premium brand such as NLS, and half bulk commercial farm feed. I think a reasonable compromise for those that want the best, but can't always afford it.
Randy Reed appears to have a decent looking product that on the surface certainly appears to be reasonably priced.
Granule size, up to 10mm. 20 kg (44 lb's) for $135.00 plus shipping.
http://www.reedmariculture.com/product_otohime_marine_diets.html
http://www.reedmariculture.com/pdf/product_otohime.pdf
Krill Meal, Fish Meal, Squid Meal, Wheat Flour, Potato Starch, Corn Starch, Fish Oil, Calcium Phosphate, Betaine, Soy Lecithin, Licorice Plant, Wheat Germ.
Made in Japan by Marubeni Nisshin Feed Co., Ltd.
They have another formula, but it doesn't appear to come in larger pellet sizes.
http://www.reedmariculture.com/product_tdo_top_dressed_oto.html
http://www.reedmariculture.com/product_tdo_top_dressed_oto.html
Krill Meal, Fish Meal, Squid Meal, Fish Oil, Haematococcus, Wheat Flour, Potato Starch, Corn Starch, Calcium Phosphate, Betaine, Soy Lecithin, Licorice Plant, Wheat Germ.
While the first formula is missing out on aquatic plant matter (algae meal/spirulina), both foods appear to have decent quality sources of protein (krill/fish/squid), and both formulas are relatively high in both protein & crude fat, so one could most certainly feed fairly sparingly. I would reckon that their vitamin/mineral levels are at industry minimums, so while not at the level of a food such as NLS, probably not way off the mark either. Most likely very similar to other bulk commercial foods. But this is why I would only feed it as a partial supplement food.
I've never used that product line so cannot personally vouch for its quality, but on the surface it looks to be a LOT better than Purina, and most of Kens formulas too. Ken simply buy food in bulk, and repacks it with his labels & name.
HTH