By single unit, do you mean with built in lens? If you’re (she’s) willing to try an SLR, my first digital camera was a Nikon d70, which seem to be available for about £50ish quid. You can find settings to work indoors quite easily, eg longer exposures. Combined with a 35mm f1.8 and/or 50mm with similar aperture (nikon 50mm f1.4 D is £50-100), you’d have something quite reasonable for your needs, and cash left over for more batteries, a tripod, etc.
Of course, other camera bodies and lenses are available for the sort of budget that’s been indicated, but I think you could have some fun picking out a kit.