Great Gatsby Holiday Party

[theansonia]

I'm going to a Great Gatsby themed holiday party in a couple weeks. I have a virgin wool tuxedo with peak lapel from Boss but feel like a vest is needed to make the look a bit more authentic. I also need a bow tie. Where do people suggest I pick up these pieces that are inexpensive since I won't wear that often but decent quality because this is a pretty fancy newport party. I'm also thinking about throwing in a scarf since much of party is outside.

Any recommendations where to purchase these items? I am not sure if I trust eBay sellers.