tool4seller Barcode Scanner is an independent product research tool developed by Tapcash Inc. for sellers evaluating retail arbitrage opportunities on Amazon. Look up products by barcode or ASIN, confirm matches, review marketplace and competition signals, and estimate FBA or FBM fees, profit, margin, and ROI before buying inventory. Estimates do not guarantee profit or selling eligibility. This tool is not affiliated with, sponsored by, or endorsed by Amazon.