Simple Green has a few varieties. The D-Pro 3 has detergent. D-Pro 5 is just a disinfectant with no detergent. I like the herbal scent of D-Pro 3 and it isn't strong so I don't have to wait too long for the cage to air out. If you have a lot of cages/tubs though you may want to use the Pro-5 and use soap and water to clean.
Here in Canada you can find it at Canadian Tire and Home Depot. In the States it is supposed to be available at Home Depot ( I saw the D-Pro 3 on the website).