sellitem

import urllib2, urllib
import json
import StringIO
import gzip


headers = {
	"Accept": "*/*",
    "Accept-Encoding": "gzip,deflate,sdch",
    "Accept-Language": "en-US,en;q=0.8",
    "Host": "steamcommunity.com",
    "Referer": "http://steamcommunity.com/id/ek-/inventory",
    "Cookie": "xxx",
    "Origin": "http://steamcommunity.com",
    "User-Agent": "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.154 Safari/537.36",
    "X-Requested-With": "XMLHttpRequest"
}

data = {
	"sessionid" : "xxx",
	"appid" : 730,
	"contextid" : 2,
	"assetid" : 118117421,
	"amount" : 1,
	"price" : 1000
}

target = 'https://steamcommunity.com/market/sellitem/'

test = urllib2.Request(target, urllib.urlencode(data), headers)
print test.get_full_url()
fish = urllib2.urlopen(test)
buf = fish.read()
print buf

Hey mate! Thanks a lot for this btw :)
Could please explain me what is the sessionid in the data dict?

Thanks!