Electronic markets have early emerged as an important topic inside e-commerce research. An e-market is a digital ecosystem intended to provide their users with online services that will facilitate information exchange and transactions. This work presents a characterization and analysis of fixed-price online negotiations. Using actual data from a Brazilian marketplace, we analyze selling practices, considering seller profiles and selling strategies. There are important factors that can be considered when analyzing selling practices, such as the seller's reputation and experience, offer's price, duration, among others. We evaluate which factors impact on the success of selling practices in e-markets, which can be used to support seller's decision and recommend selling practices. Moreover, we investigate some important hypotheses about selling practices in online marketplaces, which allow us to state interesting conclusions, such as: a seller profile can achieve success or not in a trade, depending on the adopted strategy; the offer's price and how it is being advertised are two important success factors.