What is the best and the most cost efficient way to buy BTC with USD credit/debit card?
I'm not conserned do much about privacy, but would like to avoid wire transfer.
Using services such as CoinBase or LocalBitcoins is probably one of the easier ways. You may get a better rate with CoinBase. You could also check to see if there are any Bitcoin ATMs in your area.
I have checked Local Bitcoins, and there was no option for buying Bitcoins with credit card or paypal. Also, there are no Bitcoin ATMs near my residence. Is there any other option?