I started to make a list of companies who are in the business of market your ICO to masses and so far I found:
Full Fledge (Advertising/PR + Legal):
ArgonGroup:
https://argongroup.com (Notable work: SALT, STORJ)
SuicideVentures:
http://suicide.ventures (Notable work: SONM)
ICO Box:
https://icobox.io (Doing their own ICO)
KickICO:
https://www.kickico.com (Doing their own ICO)
Pure advertising:
CoinTraffic:
https://cointraffic.io (Have a special package to promote ICO)
If you know more ressources, please let me know.
After analyze, my understanding is successful ICO have a current marketing budget of $100,000 to 250,000 USD for pure advertising (not including their bounty)