try your local pick a part, they have some good sets there sometimes if your looking for cheap mags (they pull them off the cars and put them to the side)
My local one had $160 for a set of 16s with mint tyres all around the other day. Nearly bought them but I dont need them.
They arent pretty mags though, just normal ones. If your looking for bling ones then trademes the go
most of the cheap wheels offset should be in between 38 and 45 which should be no worry.
Only other things you may have to worry about is centerbore size (ive only ever had a problem with that on my nissan pulsar which seems to have a humongous centerbore) and if your brakes will fit under them, though I cant imagine a cynos having very big brakes
and check out the sidewall size on the tyres, if its quite big or small (relating to mag size) it could throw your speedo calibration off. Also technically they can fail you on a wof if you dont have a factory wheel size... (IE you put 17s on) but they are usually pretty lenient...
Hmm, I am making this sound more difficult then it really is. Just go pick a part and buy a set of 15s in 4x100
Most of this forum know more then me, im sure someone will come along and correct me if im wrong.