์No, they should not be used interchangeably. One cannot be a proxy for the other. Consider:

Revenue = Sale + Other income 

Sale = Price - allowance - other adjustment

Thus, the revenue received from the customer may be less then price of the product. For example, an internet service is billed $50 per month less $10 voucher plus 15% late penalty. Here, the revenue by price is $50, but adjusted for discount voucher is $50 - 10 = $40 due if paid on time. If payment is received after a due date, then add 0.15(40) + $40 = $46. (Example does not consider tax). Thus, price and revenue could not be proxy for the other. We need to look at the pricing structure and billing practice of the firm.

ARPU is one of several proxies for prices. ARPU is important for every operator (and of course the target is higher ARPU) but also it is very important to know customer expirience and habits. It is important to know call mix (for voice tariffs), number of minutes, SMSs and data transfer in roaming,... Customer with lower ARPU can be "better" for operator if he/she has huge amount of voice minutes (SMSs, data transfer) inside the mobile network... on opposite, customer with higher ARPU and who has larger amount of minutes (and SMSs) send to international destinations and to other networks in country (termination costs!) contributs lower profit to mobile or fixed operator.

So, ARPU is very important but you have to know many other things about customers (call mix, SMS mix, roaming usage, ...)

Best regards,

Igor

Hi Lyndon,

The ARPU is a basic  and one of the quantitative metric used to measure the functional profitability of  a Telecommunication Service Provider of any economy. It is not the only proxy of price.