From Sary-Tash, just walk to the road leading to Irkeshtam and hitch. Most trucks will pick up hitchhikers, but some of them may also demand money. The usual fare seems to be 300 som or US5–10.
The border seems to close at
2 pm kyrgyz time. If you arrive too late and it's too cold for camping, you can stay with the locals in Irkeshtam for 100 Som.
There are actually two border posts on the Chinese side. One is 5 Km after the Kyrgyz post, where Chinese border police inspects luggage and passport and requests confirmation of onward transport. At a second post, around 120 km later, bags will be scanned once again and passports will be finally stamped.
August 2014 - Hitchhikers report that the Chinese police is enforcing paid taxis on independent travellers. They take your passport and do not want to return until transport is arranged with a
chinese driver. [[User:Rovingsnails|Rovingsnails]] and other hitchhikers were taken their passports and threatened to be deported back to Kyrgyzstan unless transport was arranged in between both border posts. Police would not accept trucks as valid transport and the taxi between both borders costs 400 Yuan ($64) for 4 people. They did not get the chance to wait and check what the police would do with hitchhikers who need Kyrgyz visa (and therefore cannot be deported) and have no cash whatsoever, as two travellers to Kashgar invited them for a ride between the borders. It all looks like an organised trick between police and taxi drivers, and as user [[User:lukeyboy95|lukeyboy95]] says above they may end up giving up on you and find you free transport, but perseverance might be needed (and make sure you are not tight with visa deadlines).
October 2015 - The Chinese police still enforces people to take the taxi and won't give back the passports until the taxi - or a bus - is paid. Even with one hour discussion, overnight camping and further discussions - there is no way to hitch between the chinese checkpoint and the immigration office. The taxi costs 100 Yuan per person (400 for the car) but the last taxi at night costs 300 yuan. In the morning there will be one bus - between
11am and 1pm, that also costs 100 yuan per person but takes people to Kashgar. It was possible to convince the driver to just take us to the next immigration office and this was 15 dollars per person (because of bad math of the bus driver we paid 20 for two people). There is also a hotel somewhere between the checkpoints in China, for the people who come too late.