You can only buy Fitch online. I get the 10kg bale. If that's too big you can get a pack of 3 compressed 4kg bales. The 10kg works out cheaper. I'm not allergic to our hamsters (about the only pet I'm not allergic too) but can be slightly affected by the smell of their urine after I've handled the litter tray - gets my lungs a bit - but only when I clean out the litter tray. So wash your hands after handling soiled bedding in the cage. That helps. Actually that sounds a bit obvious! Washing hands after handling litter tray.
Fitch First - Fitch Paper 10kg Single Bale Bedding For Smaller Critters
Fitch First - Fitch First Paper Pet Bedding