Underground forums serve as platforms for criminal communities to exchange knowledge and trade illegal goods and services, supporting an underground economy of malicious software, stolen information, financial fraud tools, and drugs. While previous research has examined criminal interactions and asset trading in Surface Web forums, and similar studies have been conducted on the Dark Web, there is a lack of empirical evidence comparing criminal activity across both environments. This study performs a quantitative exploratory analysis of trading activities in four prominent Surface Web and four Dark Web forums, comparing the types of posts to reveal that Dark Web forums exhibit higher trading activity and varying transaction types, products, and prices compared to Surface Web forums.