amazon.ca perhaps.
ebay even. but buy them from someone with an ebay store that sells quality items.
from experience, especially on the solar ones, i would spend the extra money and get the better ones.
i bought a set of 10 solar lights for around $80 and 4 out of the 10 are only working now. and I've only had them for 3 months
so now I'm going to wire them together and up to a external solar panel on my roof or something.
Even for the wired ones, the cheaper it is not only are the lights cheaper but the power source will be junk too. cheap transformers will die over time.