Where can I get a good pump carrying bag?

I bought a Lansinoh pump and I am wondering what anyone uses as a carrying case for these? All I can find online are the ones for the medelas and they are pretty pricey! I am back at work and have been lugging it around in my purse and keeping the bottles at room temperature, which I know is fine for up to 10 hours but I would rather keep the milk cold. Any suggestions?