Demi Lion summed up perfectly the different types of work for £150. This is crucial and I should've explained myself better. Shift pay for editorial/newspapers is dwindling so the above would be average. The OP is talking about a commission from a PR agency for a days' work, and in this instance £150 is not acceptable, given the commercial value of said images to the client.
Yes, I pay my bills with PR and events and occasional sport commissions, and for everything else I spec for agencies. This is not the same as working for free (although it can feel like that sometimes!), and i'm happy "chasing sales" because ultimately i'm developing a career in the top level of sport, ie. working for bigger agencies.
Editorial use of images is a business on its knees, and whilst thats another discussion entirely, I'm willing to humbly wait in line and keep honing my skills. This is deliberate - the business experience I gain working as I currently do cannot be replicated on a local level.
I'd apply the same opinions to any ad I saw in the paper. I would not be prepared to work for free where some other entity is gaining commercially, and neither should anyone else. The difficulty is there are many good amateurs who are willing to work for free or for low pay because their hobby is subsidised by other income (I hear pros call them 'weekend warriors' but I don't like that term). And amateurs are perfectly entitled to do that. Its the job of a good pro to excel beyond that competition, to reliably and consistently produce when required, not just when desired, and in all manner of situations and challenges.
Then there is the value of the image as a product, which has depreciated via commodification courtesy of many variables over time. The amount some outfits think an image is worth paying for is increasingly shocking, and it makes our work very difficult indeed. At some point we can all be forced to take underpaid work just to get by, and in doing that we all affect the intrinsic value of the image.
Are five chicken wings really worth £1? That's what they go for round my area, because that's what people have come to expect to pay.
Its hard, it really is.