Although the OP isn't in the USA. European import to Canada can be far cheaper and easier than USA import to Canada, due to the plethora of US red tape.
The best bet is probably reed or poison frogs, which might call more or less all year. For the most part, only male frogs call, and then mainly when breeding. Consequently, most frogs are silent most of the time. That might be just as well, since there's no shortage of frogs you wouldn't want to listen to. Kaloula pulchra, for instance, sounds like a rather loud cow...at 3am. The voices of many can be identified by their names: sheep, bull, bird-voice, carpenter, chorus, peeper, barking, bubbling, etc. On the whole, poison frogs have voices which are not terribly loud or abrasive, and the suggestions above might be among your best options