Make your own baby food - it's cheaper, and better for baby. Once she's on solids, get her to table food as quickly as she'll allow. It's much less stressful once she's eating what you're eating.
In terms of buying clothes, it depends. My DD grew quickly from birth to 9 months, but then didn't grow as quickly. In fact, she wore her snowsuit for two seasons, and is still at 2.5 years wearing the same pants/ shorts/ skirts that she wore at 12-18 months! So now I tend to buy better quality so it'll last. If, however, your little one is growing quickly, shop second hand - think Once Upon a Child, ask around with family members/ friends for hand-me-downs, look on craiglist/ kijijii/freecycle.
You don't need to buy many toys - inevitably that expensive toy you buy will be played with for one day and then forgotten. You can also make toys from every day things - involve them in this as well, and it'll help build their imaginations. However, I did find it helpful to buy large imaginative play toys e.g. cozy coupe car, play kitchen, sand table. These are as much fun today as they were a year ago, and will hopefully get a lot more mileage in to the pre-schooler years.
On going back to work full-time:
I'm not sure what your childcare plans are for when you go back to work - whether it's family help, nanny or daycare - trust your little one to cope with the new circumstances, and trust your childcare provider. I did not think my little one would cope at daycare and I think that 'vibe' rubbed off on her and she took a while to settle in.
Make sure daddy is involved - from feeding, bathing, bedtime. I would not be coping today if my husband were not such an involved parent.
