Sometimes you can rent them for like $5 per day.
Is there a truck stop or a camping/RVing supply store nearby? You can buy a relatively inexpensive (less than $100) portable refridgerator about the size and shape of a large cooler. The one we have will also keep food warm, so you need to make sure you have it plugged in the right way, or you will turn your refridgerator into an oven (I did this once with ours, but didn't realize it until the next morning. Warm orange juice and cold cuts? Yuck!).
They usually come with an attachment that plugs into your cigarette lighter, which makes them very portable--great for road trips and camping.
I just returned today from a work trip for 4 days (DC to Orlando). The room did have a fridge but I have been at hotels that did not. I would ask for a room close to the ice machine and pre-pack a cooler. Take breastmilk bags (ones with ziplock) and regular ziplock bags. I would just keep the milk in the cooler and change out the ice twice a day (before I left and when I returned). When I returned to the hotel there was still ice solid so I knew the milk was ok.
On my trip this week I also had to fly. So I packed my cooler, w/ice full of 60oz. (divided into 3 & 6 oz bags) double bagged in ziplock bags, into my suitecase and checked it. It was perfect when I got home despite the broken handle on my suitecase. it's a pain, but it can be done.
thanks for all ur great responses ladies. didn'y get chance to be online before now. returned yesterday from trip. exhausted. baby didn't seem to recognise me
but later she latched willingly but her clench hurt. my nipples burned...weaning time is around the corner i tell you...