iPhones in China will be relatively expensive, but monthly charges will be among the lowest in the world.

So says the Xinhua News Agency, the official press service of the Chinese Communist government, quoting an unnamed “insider” at China Unicom (CHU).

According the Xinhua report published early Friday, China’s No. 2 carrier will roll out the iPhone shortly after the Oct. 1-8 National Day holiday in four models: 3G 8GB, 3G 16GB, 3GS 16GB, and 3GS 32GB.

The entry-level version, the 8GB iPhone 3G, will cost 2,075 yuan ($303) according to this report — more than three times its U.S. retail price ($99).

But the iPhones in China will be bundled with two-year service packages that are considerably cheaper than AT&T’s (T). According to Xinhua, the lowest-price service package will cost 126 yuan per month, about $18.45. (AT&T charges its U.S. iPhone customers a minimum of $39.99/mos. for voice service plus a mandatory $30/mos. for data.)

Total cost for China Unicom customers over two years: $746. Total cost for AT&T customers: $1,779.

These prices are slightly different than those quoted by China Business Times earlier this week. According to that report, China Unicom had set an “internal launch date” of Oct. 15 for two models: an 8 GB iPhone 3G selling for 1,999 yuan ($293) and a 16 GB iPhone 3G for 2,999 yuan ($439). Both models were said to be offered with 2 year contracts starting at 186 yuan ($27) a month.

China Unicom announced late last month that it had struck a deal with Apple (AAPL) to carry the iPhone in China, beating out giant China Mobile (CHL). China Unicom has 140 million subscribers; China Mobile has nearly three times that many.