Buying from localbitcoin site is more expensive than buying using credit cards technically but it depends in the site you will use to buy btc. You can just but some on coinbase if you want too I think they support credit card in buying btc. It is much cheaper to buy in coinbase IMO since prices are near the current market price. There will only a fee though but it won't be that expensive. For guides go to this site. https://www.buybitcoinworldwide.com/en/buy-bitcoin-credit-debit-card/