Please help question about leverage.

Hi,

The only way to loose the money when buying or selling without leverage is if the market goes against my position to 0% correct?

Example:

If I buy without leverage (1:1) 200 barrels of oil at $6000 therefore each barrel costs $30, for me to loose all the money, the price of barrel would have to go down from $30 a barrel to 0, correct?

Yes, you are right - at 1:1 leverage, you'll loose your entire money if the stock you bought goes down to 0.