This paper reports findings of two field studies, conducted on a local online auction website, that compare bidding strategies in charity and non-charity auctions, focusing on the extent of jump bidding at different stages of auctions. Results indicate that jump bidding is negatively correlated with bidder entry and positively associated with ending prices. These correlations are greatest during the beginning stage of auctions and are substantially larger for charity auctions than for non-charity auctions. Additionally, early-stage jump bidding occurred more often in charity auctions (consistent with bidders trying to drive up prices in charity auctions), ending-stage jump bidding was more frequent in non-charity auctions (possibly used strategically to win the auction). Further, frivolous products tended to sell at a higher proportion of retail value in charity auctions, providing a replication of the results of previous researchers but in a field setting.