The increasing number of online auctions poses a big challenge to e-consumers, especially to those who are actively looking for good deals. In this paper, we present the design of an autonomous agent that can alleviate some of these problems by participating across multiple online auctions (in particular, English, Dutch, and Vickrey auctions). The agent makes decisions on behalf of the consumer and endeavours to guarantee the delivery of the item according to the user's preferences. Our agent monitors and collects information from the ongoing auctions and determines which auction it wishes to participate in. The decision on how much to bid in the selected auction is made based on a series of tactics and strategies. The proposed bidding algorithm has been implemented in a simulated marketplace environment and its performance has been evaluated empirically. 1