Arbitrage on Eagle Coin Sets?

American Eagle 20th Anniversary Silver 3-coin sets are available from the US Mint for $100 + $4.95 shipping.

These exact same coin sets are selling on Ebay for $160 - $175, + $5-$10 for shipping.

The only difference is that coins on Ebay are available immediately, and the coins from the Mint will be shipped in early December. But being willing to $60-$75 extra for delivery in November vs. delivery one month later in December for $100, is about a 720%-900% annual interest rate. Annualized interest rates at Paycheck Advance operations are often less than that, see some rates here, showing that 14-day rates are "only" 460% on an annual basis.

Arbitrage profits anyone? You can purchase up to ten sets from the US Mint!