From a comment (which gives a link I cannot access where I am now) in the article the OP linked above:
The vendors will have payment records for the FBI to look through. In Hillary's mind, the wedding is a justifiable Foundation expense. Probably listed it as a fundraiser on the 990 for 2010.
According to estimates and reports, the $2 million to $5 million event held in Rhinebeck, NY included:
$750,000 for catering, according to Brides magazine deputy editor Sally Kilbridge
$11,000 for the cake, which is reportedly gluten-free
$250,000 worth of jewelry for the bride
$109,000 for the tables and crockery for around 400 to 500 invitees
$600,000 in air-conditioned tents, complete with glass walls
$200,000 in extra security, paid for by the Clintons
$15,000 in high-class toilets, according to online gossip site TMZ
$500,000 in flowers arranged by Jeff Leatham, who’s worked with Madonna and other celebrities
Wine as a party favor from Clinton Vineyards (which has no relation to the presidential family)
A Federal Aviation Administration-enforced no-fly zone from 3 p.m. Saturday to 3:30 a.m. Sunday over Rhinebeck, the small New York town that includes Astor Courts, a picturesque mansion that’s hosting the event and overlooks the Hudson River.