Basically, im buying enough bitcoin just to pay for the item, which is approximately 400 USD. I have no interest at this time in holding on to any. Do i still need a wallet?
Any time you're willing to pay for something and receive that something in return you're risking the seller not closing the transaction with you.
I'd engage in the transaction you're talking about ONLY if the seller is offering to put your bitcoin in an escrow account until payment has ben received or they send you the bitcoin first.
If you offer payment, you have no recourse if they don't bother to send you the Bitcoin you purchased.
So it sounds like I have to find a live human to buy the bitcoin from? Is there no way that its automated? Like i cant just go to an exchange, enter the amount of BTC i want, purchase with my credit card, receive the key, and then use it to buy the item i want?
This is all very alien to me.