1) Accommodation is free in certain circumstances. There's a myriad of things for when you pay/don't pay but it can be summed up as: on ship = free; ashore and on course = pay.
2) Phase 1 will take out amost £5 per day for food (I'm aware it's less, but AFPRB is pretty close to being announced). ALL Naval establishments are PAYD, 97% of RAF units are PAYD and 70% of Army units are PAYD. So, depending on your branch, you could be lucky and posted to a "Tri" Service unit, run by the army, and you'll have the privilege of being charged for food that's worse than what gets offered at PAYD (personal experience speaking here).
I (probably unhealthily if you believe the propaganda), only really eat 1 big meal a day, and hardly every bother with breakfast. Therefore, pre-PAYD, I used to feel seen off that I was paying for food that I wasn't eating. And let's be honest, at RN establishments at least, the food wasn't great.
PAYD is much better for me financially, as I have a choice where to go for my evening scran, and don't get charged for food I'm not eating. The PAYD food at the (RAF & Army) recent bases I've worked at isn't bad at all; maybe it's a bit more portion controlled than before, but that's not a bad thing (no 'round-the-buoy' for the fat ChOps(R's) et al).
RAF Digby isn't PAYD. That's the only place I've visited in recent years that isn't.