I don't think so. I searched, and couldn't find a triangle holder at any price, except for from Classic Billiards.
The only alternative is to find a local pool table mechanic or mover who has a garage full of parts. There's one such guy in Hartford, CT. I don't know that he's so keen on shipping things, though. Maybe there's a similar guy in your area.
That said, it's a one-time purchase. If you need one each, it's $135 with free shipping.