I personally prefer Pet City in Wishart who I think are very well priced, I went to a local independent pet store the other week and was horrified at both price and quality... Oh, and PC have a range of both mice and rats in incremental sizes from
pinky-fuzzy-hopper-weaner-adult,
and the little place had:
pinky/fuzzy-weanling-adult
The fewer choices of size was kind of disappointing, and there wasn't really a consistency in the sizes they had! Not to mention the mice defrosted in the water, leaving behind really dirty water, whereas the PC rodents are by comparison exceptionally clean, rarely ever changing water clarity at all... Gives me peace of mind that they are conscious about hygiene standards etc...
If you haven't tried them, go to Pet City and I reckon you'll be happy...