Bombing Syria

I'm a fairly ordinary person. I try to be well informed, but I'm not "Brain of Britain". Generally speaking I question things & try to find answers.

I don't understand 2 fairly basic things about the government's decision to bomb Syria.

Firstly, given that we have had 7 years of cutbacks & recession due to the mess the banks landed the world in, how can we suddenly find the £millions it will cost to be an active part of the bombing campaign? Where has the money come from? If it was lying in some deep pocket somewhere how come we have just had a financial statement which continues the drastic cuts & the hardship well into future years when the deficit is not getting any smaller?

Secondly, given that oil is a precious & finite resource which the world depends on, how come it's OK for that same oil to be the target of the bombing.What possible sense is there in blowing millions of barrels of oil up? I know it generates income for ISIS, I'm not daft. But surely it's criminal to destroy a non renewable, major, fossil fuel resource now we have passed "Peak Oil"? Aren't there other, better, ways to defeat ISIS & cut off their money supply?

Is it just that dropping bombs is the easy answer to look as if we are doing something useful?