There are many exchanges and places where you can buy not just Bitcoins but also other altcoins. Transactions are instant in most of these exchanges and most accept different -- actually many -- payment methods including cash.
Below is a list of some of the most common ones.
Available to over 30 countries as of this year, Coinbase is probably is the world's largest Bitcoin broker. It lets users buy Bitcoins with a credit card or debit card and charges and you get the coins instantly. The exchange charges 3.99% fees for credit/debit card purchases. You have the option to use a connected bank account for a lower fee of 1.49% but the coins are delivered after five days.
You can also buy with SEPA transfer, Interac Online, Xfers Transfer and other payment options.
You can also purchase and sell Bitcoin, Litecoin, and Ethereum.
Bitstamp is one of the world's largest and known Bitcoin exchanges. You can purchase Bitcoin using bank transfer, SEPA transfer, international bank wire, and now even credit cards. It charges a 0.25% fee, falling to 0.1% with sufficient trading volume.
It also allows trading of other cryptocurrencies including Litecoin, Bitcoin Cash, Ethereum, or Ripple including deposits and withdrawals.
The Hong Kong-based multi-asset trading exchange Bitfinex is one of the largest Bitcoin markets in the world. It allows customers to buy Bitcoins through bank wire only at a very low fee of 0.1%. It is a very advisable market for those intending to buy a large number of Bitcoins though was hacked in 2016.
It also allows fiat or bitcoin to margin traders at interest.
On it you can trade Bitcoin, Iota, Litecoin, Ethereum, Bitcoin Cash, EOS, Monero, Ethereum Classic, Dash, Ripple, Santiment, Zcash, BTG, NEO, YOYOW, OmiseGO, Streamr, QASH, Qtum, ETP, Eidoo, and Aventus.
You also access leveraged margin trading through peer-to-peer funding market.
Kraken exchange was founded in 2013 and is world's largest Euro-dominated Bitcoin exchange based on daily average trading volume. It also allows trading of Ethereum.
It serves customers from other countries including European, Canadian, British, and Japanese customers. Deposits are made through bank wire, SEPA, SWIFT, and bank deposit (Japan only).
Coinmama works in almost every country and charges 6% fee on each purchase and you can buy Bitcoins with a credit or debit card. Identity verification is needed if buying less than $150 worth of Bitcoins.
It also sells Ether and you can send coins to any wallet.
GDAX is owned by Coinbase and allows you to fund accounts with bank transfer, SEPA, or bank wire.
It allows users to trade USD and Euro for Bitcoin, Ethereum, and Litecoin, British Pound (GBP) for Bitcoin, as well as Bitcoins for Ethereum, and Litecoin.
CEX.io allows buying and trading of cryptocurrencies, such as Bitcoin, Litecoin and Ether for fiat including variety a of other local currencies. You can buy with VISA/MasterCard and card purchases are delivered instantly.
It covers 99 percent of countries.
ShapeShift also allows users to trade Bitcoin with Litecoin, Ethereum, Monero, Zcash, Dash, Dogecoin and many other altcoins without an account. In fact, you can trade any Blockchain asset for another on this exchange.
However, you will need another cryptocurrency to buy Bitcoins. It works in almost all countries and the exchanges are almost instant. You can even follow the most recent transactions (without names or addresses) on their website.
LocalBitcoins is an escrow service to match Bitcoin buyers and sellers and the most common payment method is cash deposit although there are a variety of methods available even local ones. You can buy instantly via an in-person meeting without any information, privately and easily. However, beware of scammers.
BitQuick is one of the fastest ways of buying Bitcoin in United States where a customer browses offers, selects an offer and then visits a bank to deposit money in the seller's account, and he or she will receive Bitcoins within an hour.
The New York-based Gemini Bitcoin exchange also serves residents from UK, Canada, Hong Kong, Japan, Singapore and South Korea. You can buy Bitcoins through wire transfer, SEPA or ACH transfer.
The exchange is licensed for Bitcoin and Ether trading and is regulated by New York State Department of Financial Services (NYSDFS).
Mycelium Local Trader
Mycelium Local Trader facilitates trades at no fees at all. You can find local Bitcoin traders and meet up in person to trade without any fees.
No information online to exchange.
Other markets include Bitcoin-otc that acts like a Craigslist for Bitcoin and charges a flat fee of 0.10% per transaction; and Cancoin, a P2P Bitcoin exchange and multisig wallet currently available in USA and Canada and charges no fees
itBit, a a global Bitcoin exchange which is licensed by New York State Department of Financial Services and available in all states except Texas. It also acts as an OTC desk and charges takers from 0.20% for 0-8000 trading volume. Higher volumes are charged higher.
CoinBTM provides 40 kiosk or machines across NY and New Jersey where you can buy Bitcoins with just a phone number as the requirement. You can find the nearest using an online map.
VirWoX facilitates, primarily, buying of Second Life Lindens (currency used in Second Life -- a virtual world) with a variety of currencies such as EUR, USD, CHF, GBP, OMC and ACD and you can trade those Lindens for Bitcoins although it is very costly -- 10% in fees. You can also buy Bitcoins with PayPal directly.
Bitcoin ATMs allows users to buy Bitcoins with cash. It can be a quick and easy way to buy Bitcoins although most ATMs have a fee of between 5-10%. You can a``lso find ATMs on the map.