What's the best Amazon seller tool for beginners?

It depends on your model. For arbitrage sellers, a sourcing app like SellerAmp or BuyBotPro — with built-in price-history and ROI checks — covers the buy/no-buy decision cheaply. For private label, an all-in-one suite like Helium 10 or Jungle Scout bundles product research, keywords, and listing tools behind one subscription. Start with the one tool your first ten decisions actually depend on, then add as your workflow reveals real gaps — not before.