Check with your state's laws, but in my state, we are required to list the value that the donor said the item is worth. I think it's a good practice to get into. Most auction guests at first of the deal they are getting, then they compare what it is valued at to continue bidding, then they think about the "cause" and are willing to get above market value on an item they want to be the winning bidder on.
Furthermore, most organizations I work with start bidding at 30% which is standard, raising the bid by 10% each time, and have a guaranteed bid at 150% of value. We increase these bid increments for our Super Silent items, which guarantee bid at 300% of value.
Most auction companies say that an average return of 70 - 75% of value on silent auction items is good. If you're getting more than that, then your crowd is okay with what you've been doing, so keep doing it!
In the past, in addition to a minimum bid, we noted a minimum incremental bid. Not that you would necessarily have a problem, but this avoids people outbidding the person before them by a penny.
<img src=images/smilies/smile.gif> <font color="#"Purple"">Make it a great day!</font>
We list the retail value (or an approximate value if it's not known for sure) on the bid sheets. We also generally do starting bids at 50% but for some items that we know will be more popular (such as American Girl dolls, Wii, etc), we might start it even higher than 50%. Most of our items go for at least their retail value, with the majority being above retail.
