what is the best website to buy btc?

[UconBit]

Like others mentioned above, it depends on where your money is coming from. Some countries have tighter regulations than others which make it harder to purchase bitcoins locally. There might be a good local seller where you live that can accept local bank transactions for cheaper than the others, and then you can just transfer it out to another broker. That's what I do: buy local then send it out to Binance (they don't accept fiat)

Bitstamp seemed to be the most reliable international one with reasonable fees that I could find. Why Paypal though? Any transaction through Paypal comes with high commissions.

[crypteris]

Well, some exchanges, which were named here are quite reliable, you can try ‘em. But I’d also like to mention cex.io. But I think I should make a remark that they don’t operate in each state. So, you'll need to check this information first. As for other things, cex is a great choice, because they allow debit cards as a payment method. Their fees are quite reasonable too.
Besides, fees may lower in addiction with volume trade.

[galinskiydmitriy]

Try using the localbitcoins service. I've been using the service for about 1 year and for me it's the fastest, most profitable and convenient way to buy Bitcoin.

[slackcryptoz]

Buying of cryptocurrency is much simple than ever, for me it is good to buy through localbitcoins, it gives the access to almost all form of payment access. Similar thing cannot be expected with every exchange service as there are some which accept only certain payments.