Each delegate decides if they want to pay for their own vests. That's the only thing that the rank and file members aren't paying for.
Here's what the members are paying for:
Each delegate's and alternate's round trip travel expenses.
Each delegate's and alternate's hotel room for 5 or 6 nights, at the Paris or the adjoining Bally's Hotels
Each delegate's and alternate's meal allowances, which is at least $75 per day
Each delegate's and alternate's salary if they are Union employee, or 40 hours of regular-time pay for the week for any rank and file members who are delegates or alternates
Also, maybe the hall rental, although maybe the Paris gives it to them for free because the Teamsters are paying for more than 15,000 room nights.
Then there are convention speakers from all over the country and some from places such as Australia.
And musical bands, and the company that televises the convention inside the hall, and the company that transcribes the daily proceedings, and the company that produces all of the graphics and the videos. And the company that prints the hand held signs, such as TEAMSTER POWER, etc., etc.
And there was some choreographed 10 or 15 minutes where Local principal Hofficer after Joint Council principal Hofficer stepped to the mic and said, our Executive Board also voted to approve $5,000 (of the members money)(for some kind of cause.)
The members also have paid (unknown to them) to have dozens of Teamsters-owned tractor trailers driven to Las Vegas (and back) so they can drive down the Las Vegas Strip and parade in front of the delegates for a few minutes: