Whmcs Payment Methods

That's a good point, you should never just look at the price. The cheapest provider is of no use if, for example, the support is poor and you are alone in case of problems. A failure can quickly become expensive.
It depends on the majority of users you have on your platform; for example, we have customers from India, and we have three gateways live at the moment.

  1. PayPal
  2. Razorpay
  3. CoinBase
PayPal and Stripe are top tier. If you run a large scale business, an actual Authorize.net merchant account is the way to go. As far as Bitcoin, I have heard Bitpay work well.
We were using paypal recently but due to change in policies and lot of other issues. I have stopped using paypal and now working with bTCpay. strip , perfectmoney.
WHMCS can get integrated with many payment solutions. We are using perfectmoney , btcpay server for crypto and Strip as fees are low and you are more secure from chargebacks in the future. Paypal is charging high transaction fees as well as chargeback issues . Conversion cost is again very high, lot of times account get limited and many other similar issues.
Paypal, 2checkout and stripe, all of them offers different fee structure based on features. At this point paypal charging highest fee and very bad exchange rates if you are not USA based.