I plagerized a list I got from a pro FSA web site click here You can check out the difference
1-Selling electricity and gas to the Syrian Government through ISIS controlled dams like Teshreen, Al Ba’eth and Euphrates dams, in addition to Tweenan gas field.
2-Taxes it imposes on Al-Raqqa citizens. Every house should pay $800 Syrian Liras for electricity bills and $400 for phone bills. Each shop should pay $1500 for electricity bills & hygiene services $400 for phone bills. (Al Hisba apparatus is a special ISIS agency concerned with collecting taxes from citizens.)
3-Customs revenue & Commercial Trade. ISIS imposes taxes on any goods that is being exported or imported. Raqqa city and Mosul are their biggest areas for these ops. ISIS exports fruits, vegetables, cereals and grains, clothes and fabrics to Al Mousel in exchange to importing dates, vehicle spare parts, and some electric tools. This trade, which is…