I have spent a LOT of time searching for Trilliums this year.
The small FB market in BC is more expensive then anywhere else in Canada and with gas prices going up I expect that will continue. On my 1976 I just bought there were 4 others inline to purchase it and on the 1972 I just sold there was a ton of interest - sold it sight unseen over the phone in a day.
Honestly, I have not seen a decent quality Trillium
under $4500 in BC this year, and though I don't monitor the web for Bolers as much I know on Vancouver Island there hasn't been anything decent under $4000 and right now they all seem to be running over $5000.
There was (and might still be) a Trillium
in Surrey at a used store that was under $4000 ($3700). It had been painted outside and looked pretty rough. The inside FB looked good but the cushions were destroyed - one look inside and we passed on it. There was also a trashed Trillium for $1500 that sold in 2 hours last month (just missed that one)
If you don't mind driving then there can be some great deals in Calgary or Edmonton. There was a 4500 in amazing shape for $4200 last month. I recommend checking http://usedcalgary.com
or calgary.kijiji.ca. They don't seem to use craigslist in Alberta.
The other thing you can try is driving around looking for the abandoned trailers and offering to purchase them.