you should be able to get dry ice from your local grocery fish counter or meat counter (for free i believe, but maybe you have to buy some meat or something?). we use it at work all the time (i'm a biologist), just be very cautious about handling it, use oven mitts, because it's really cold! i've handled it numerous times with bare hands, but for only a second to throw it into a bucket or the sink and i haven't burnt my fingers off yet. that being said, when i'm actually handling the ice for real (not just to throw a rogue piece that fell on the counter into the sink) i definitely take precautions and use our special cold gloves. a couple of pellets last a long time, so you really don't need much.