How much it cost to apply China visa in Hongkong? And where?

No, Indonesian is not allowed to apply for China visa in Hong Kong.
But you can try if you have return air-ticket, hotel reservation; have been to China before and your visa to China has never been canceled. However, it is not 100% sure, so you'd better apply for one in your own country.

Yes, Indonesians are banned from getting Chinese visas in hk.

However, with the following requirments, you may get SINGLE entry China visa valid for 15 Days in HK:
Previous used China visa on a new or an old passport;
no cancelled china visas;
a confirmed return ticket or a ticket showing exit from China;
a confirmed hotel booking voucher.

Another way to get a China visa in HK is to get one through CTS at Hong Kong airport. They will help apply for a China visa at certain fee. I'm not clear about the exact fee charged by them.

With a Shenzhen visa, you can only visit Shenzhen and stay there up to 5 days; there is no Guangdong visa; with a China visa, you can visit anyplaces of China mainland, including Shenzhen, but except Tibet.

i really appreciate all of your answer...Thats too bad since the fee to apply China visa in my hometown can reach US$60 (i use USD to be easy), that is a lot for me...Once again, thank you very much