For 3.x I never allowed mass custom wondrous item designs for PCs or world background, so no 1/round create food and water dispenser. Or equal level and cost 1/round fireball throwers either. Such items blow away every existing item and spellcaster for efficacy and balance.
The guidelines in the srd are directed at pricing a DM's new item concept, not a system for characters to craft anything by simple application of the formula the way wands and scrolls and potions are set up to generally do any spell within their limits.
The closest for efficiency would be a clerical wand of create food and water which would be 50 charges per creation.
Or the
sustaining spoon which feeds 4 humans with gruel per day for 5,400 gp.
A 3.5 cleric can spend 10 minutes and a third level
create food and water spell to create daily bland food for three people, enough for a small party or for higher levels really dedicating themself exclusively to it enough for a small group, but not really enough to support even a small village on their own.
So blind cave fish farms and fungal factories for my dwarven undermountain kingdom.