Next cheapest found were $115 per side IIRC, from British and US suppliers. Might have found them a little cheaper and with quicker shipping with a lot more searching. And of course salvage yards would be even cheaper. But last time I tried searching the salvage sites I've seen mentioned on the forum, back when this swap was first suggested, I had no luck. Not surprising since Titanium Wagons are probably the smallest section of TC sales so spares from wrecks would be few and far between.
Once I found some at a price I was willing to risk, I hit the buy button.