I don't know the capacity of the Tetenal - I looked at the prices and went "duh, I know which I'm getting". The Kodak ones are packaged as 4 sets of bottles so you can make up 5L and keep the rest as concentrate (or sell them!) without opening. If anyone in Australia wants a Kodak 5L RA4 kit for $40, PM me as I still have one spare.
Originally Posted by Rudeofus
The Kodak requires about 10mL of replenishment per 8x10", so all up cost (with shipping) in AU is 8c/sheet. Certainly it's a good price, but it's not like the chemistry is inherently expensive (PtCl2!) or hard to make. And the shop is for real; they're an APUG advertiser and I've bought that very set of kits from them myself, as well as the Fuji C41 and E6 offerings.
PE: I think the stop/fix suggestion above was intended as replacement for a stop bath, not something to do between a stop and a blix. Since fixer is pretty acidic, it will act as stop and have the neat side effect of reducing silver load on the blix. Due to the high cost of (presumably B&W rapid) fixer vs acetic acid and the low price of RA4 blix as stated above, I don't see much point though.