Sorry to hear your DH has lost his job. I take it your ds isn't at school yet? No hope of moving house to a better catchment area?
Can't really help you with the decision but just wanted to give you a snapshot of our costs.
In terms of the costs, our fees are £3000 per term per child, that includes everything - trips, lunch, books, etc. - except uniform. Fees have gone up about 5% this year.
I'd say the uniform costs about £200 per year - blazer, outdoor coat, shirts and trousers and PE kit. We're lucky in that most of our uniform (eg standard grey trousers and shirts) you can get at M and S or Asda, but you do have to pay lots for the blazer £70 and coat £30. There is a second hand shop too so I guess the cost could be reduced that way. Some schools have exclusive suppliers so be warned. Some do charge extra for things like lunches, this can mount up at say £2 per day.
I do know there are plenty of people at our school who struggle to pay the fees, so I'm sure you're not the only person feeling this dilemma. Obviously people have all sorts of reasons for making their choices, but many are trying to get their dcs into the local grammar at 11, so they figure that spending now gets them a head start.
I'd recommend that you check what is and isn't included at any school, as trips, lunches etc could really add to the cost if not included.