This depends on the specific Apple model and the number of installments. Different banks have different handling fees for different installments. The following takes the latest iPhone6s as an example:

When purchasing iPhone6s in three installments, Agricultural Bank of China and China Merchants Bank credit cards are the most cost-effective, with zero handling fees.

Purchasing iPhone 6s in 6 installments will require installment handling fees. Judging from the total handling fee amount, ICBC's 95 yuan is the lowest and most cost-effective, followed by Agricultural Bank of China and China Merchants Bank in third.

Banks that support 9 installments require installment handling fees. Judging from the total handling fee amount, the two most cost-effective banks are: Industrial and Commercial Bank of China and Bank of China. The installment handling fees of other banks are more than 300.

Twelve installments require installment handling fees. Judging from the total handling fee amount, the three most cost-effective banks are: Industrial and Commercial Bank of China, China Merchants Bank, and Agricultural Bank of China. The installment handling fees of other banks are mostly more than 400 yuan.

Most of them support credit card installment payment in 18 installments, and all require installment handling fees. From the perspective of the total handling fee amount, the two most cost-effective banks are: Industrial and Commercial Bank of China and China Merchants Bank. The installment handling fees of other banks are mostly 600 to 700 yuan.

Most banks support credit card installments in 24 installments, all of which require installment handling fees. Judging from the total handling fee amount, the three most cost-effective banks are: Industrial and Commercial Bank of China, China Merchants Bank, and Agricultural Bank of China. The installment handling fees of other banks are mostly 800 to 900 yuan.

In general, when buying iPhone 6s by installment, China Merchants Bank, Agricultural Bank of China, and ICBC are the most cost-effective.