What are "Normal Resell Rights"?
Normal resell rights mean that after you buy the item you will be allowed to sell it to your customers. There may be limitations, like that you can only sell the product for a specific price.
What are "Master Resell Rights"?
When you acquire master resell rights, not only can you sell it to your customers, but your customers also have the rights to sell it. You can also sell master resell rights to your customers, so they too can sell resell and master resell rights.
What are "Private Label Rights"?
With private label resell rights, you may not only resell the product but you may also edit the content or product and claim it as your own work (meaning, you become its author).