How it works
A message says a supplement or energy-drink brand loves your channel and wants to send you a free starter kit, a shaker, a tub, maybe a hoodie. There is no talk of paying you, which already tells you this is gifting and not a paid sponsorship. To ship the box, they say, you need to cover a small shipping and handling charge, usually 8 to 20 dollars, on a checkout page they link. That page is the whole point. It either pockets the shipping charge and vanishes, or it captures your card number and billing address to sell or reuse. The free product does not exist.
The tell-tale signals
The loudest signal is being asked to pay shipping on something described as free. Real gifting costs the creator nothing, ever. The sender is almost always a personal Gmail or Outlook address dressed up with the brand's name, or a lookalike domain with an extra word bolted on such as teamgfuel or gfuel-gifting. The link often runs through a shortener so you cannot see where it lands. Expect a deadline, claim your box within 48 hours, placed there to stop you from checking.
What to do
Do not open the checkout link and do not enter a card. If you want the product, go to the brand's real website and find their official creator or affiliate program, then apply there yourself. Reply from a fresh note asking for the offer in writing on the brand's own domain, with a brief and a contact you can verify. Put the original email through a risk assessment before acting on any part of it. If you already entered a card, treat it as compromised and call your bank.