Comparisons

Buying crypto with a bank transfer means moving currency from your bank into your exchange account over a domestic payment rail and then placing the order from the cash balance, which is normally the cheapest way to fund an account and differs from card funding mainly in speed and in the withdrawal holds that follow.

Apple Pay and Google Pay are wrappers around a card you already hold, so on an exchange they are priced and treated exactly like a card deposit, while PayPal is a separate funding method with its own availability and its own fees, and all three settle instantly and then sit under a withdrawal hold.

Dollar-cost averaging means buying a fixed amount of an asset on a fixed schedule instead of all at once, and on a crypto exchange you run it either as a recurring buy the platform executes for you or as an order you place yourself each period, which is mostly a decision about fees.