Ok, the best "bang for the buck" scenario with the Agfa-120 developer is buying 10lbs of Pot Carbonate, 3lbs of Hidroquinone, and 10lbs of Sodium Sulfite (I'd need 7.5), which comes to $108.80 and yields a little over 56L of developer. that's about $2 per L. Plus shipping
LPD costs $6.99 and yields 22.8L at a 1:6 dilution. That is about $0.30 per L. shipping would be 5-6 bucks max.
and then there's photog's formulary 106... $21.5 for 16 liters, or $1.35 per L.
BTW, I'm posting these things in the hopes that it will be useful to someone else, but I''d also like to hear people's experiences with these developers (particularly with neutral tone papers). Thanks