Yes, you can buy .5 bitcoins with cash using a Bitcoin ATM. The process is relatively simple, but you will need to have a valid government-issued ID in order to use the ATM. Once you have found a Bitcoin ATM that supports cash transactions, insert your ID into the machine and select the “buy bitcoins” option.
Enter the amount of cash you wish to spend, and then confirm the transaction. The bitcoins will be sent to your digital wallet, and you can then use them to make purchases or send money to others.