I've always thought that you need deep pockets and patience to trade oil. Price is so volatile and, as it affects every car owner, it's politically hyper-sensitive.
Professionals and serious retail oil traders are mainly trading futures with all the back months and looking at cantangos and backwardation issues, etc, and that does require capital.
But many quality retail forex brokers also offer oil as a CFD contract, alongside their other CFD offerings. These are usually based only on the current front month futures contract and are offered in units as low as microlots. But oil, like indices can move fast and far and therefore can still represent a big risk and potential even with small lot sizes.
Crude oil is used primarily for fuels, but a lot of that fuel is used in industry and industrial transportation and not just for private cars, so economic demand factors, as well as supply factors, weigh heavily on the price.
I am not sure what affects consumer petrol prices the most, crude oil price or the taxation policies of the national government in the country concerned.
