My best luck so far with online jackets and waistcoat was from a for-hire shop that was changing it's stock. the agryles they stocked were no longer being produced so they decided to sell off the old stuff. I got away with well under $200 for a black argyle and vest, shipping from the UK included. The other route is to find a suit jacket/blazer and have it converted. You'll need a good tailor for that one though, and I was lucky enough to find one. It was $87.50 to have a jacket converted and it turned out well both times