Acording to the SRD...
Prestidigitations are minor tricks that novice spellcasters use for practice. Once cast, a prestidigitation spell enables you to perform simple magical effects for 1 hour. The effects are minor and have severe limitations. A prestidigitation can slowly lift 1 pound of material. It can color, clean, or soil items in a 1-foot cube each round. It can chill, warm, or flavor 1 pound of nonliving material. It cannot deal damage or affect the concentration of spellcasters. Prestidigitation can create small objects, but they look crude and artificial. The materials created by a prestidigitation spell are extremely fragile, and they cannot be used as tools, weapons, or spell components. Finally, a prestidigitation lacks the power to duplicate any other spell effects. Any actual change to an object (beyond just moving, cleaning, or soiling it) persists only 1 hour.
I assume you have a ring that would allow you to use the spell at will? In effect you would always (rather than just for an hour each casting) be able to clean any item, soil any item, change its color (although it would regain its normal color in an hour), change the taste of food you are eatting - or another is eatting, never have to drink cold coffee or luke warm tea again, etc. You could also create very small and simple objects made of simple non-valuable material at will (a child's top, a shiny quartz pebble, etc) but they would cease to exist an hour later. This could make 'now you see it, now you don't' tricks quite easy. Use a created pebble and allow it to cease to exist. Then create it anew in the hand with the ring when showing where it supposedly really was. A con man with three cups comes to mind .
Hmm, it specifically mentions slowly moving objects of up to one pound as a change that can be made with prestidigitation. Being able to move a small key lying on a table could be useful. Of course, you could not move it through the air, and I imagine most DMs would limit you to only objects within a 10 to 30 feet of you, but it could be useful. Perhaps as a distraction you could slowly move a small branch and then let is snap back. If this occurs 30 ft to the left of you it might allow you to surprise a guard / foe. Or you could lift a small rock, move it several feet away from you, and then drop it behind a guard / foe. Or drop it on their head. It can't cause damage, but it would definately distract them - likely causing them to look up for the cause rather than at you.
Hmm, you can make crude simple objects of up to a pound in weight. They are too fragil for use and they fade after an hour, but with a very good bluff check you could perhaps sell such an item for sub-normal cost. Of course, anything more than zero would be a gain - until they came after you to get their money back. Most light weight clothing only weighs a few pounds. A few uses of Prestidigitation and your clothing is a different color - at least for an hour. But if a certain color is worn by all of a certain group then perhaps you could use this to gain a small (+2) bonus to disguise checks to blend in with them.
You cannot heat/chill something enough to cause damage, but you could make somewhat uncomfortably hot/cold for an hour. Granted, they would only be sweating/shivering and not taking any damage, but if you are in a game where role playing is as important as roll playing then perhaps this could be useful. "Just think what I might have done to you if I had
really been angry!" etc.
That's all I can think of for the moment. Actually, for 1000 GP that sounds quite useful, albeit circumstanciual. In hack/slash campaigns it wouldn't be worth much, but in any game with a significant amount of role play and tactics (not 'rush in and kill anything in the way that's moving') this could be a good buy.
