The idea of automating e-commerce transactions attracts a lot of interest among researchers and IT practitioners, and multi-agent systems are claimed to be one of promising software technologies for achieving this goal. Since price negotiations are one of crucial aspects of e-commerce transactions, in this paper we present a rule-based implementation of automated price negotiations utilized in a multi-agent system that models an e-commerce environment. We start by summarizing state-of-the-art in rule-based approaches to automated negotiations. We follow with a brief description of the conceptual architecture of our system and a simplified scenario that involves multiple buyer agents participating in multiple English auctions performed in parallel. A detailed discussion of the design and implementation of price negotiations, using JADE and JESS, and presentation of sample experiments complete the paper.