Investigating the dealer of the product you plan on bidding is not really a really bad idea since this can help you get a document of their history which means you can check if they have done any kind of deceitful sales in the past or not. We market particular ebay items and mouse tapping these products will redirect you to its corresponding ebay listing page.
Make your bid close to the last parts of the bidding. This will allow you to get the bidding range of the product and for that reason determine if it's within your bidding range. Check if an auction site you're planning on putting in a bid offers proper protection for purchasers. This approach will be helpful and protect you from frustration in case you experience a fraudulent vendor.