That's just the way things are. Both of my boys ran over $200 right off the bat. Their adoption fees were low, around $65 but they both got colds and I had to have the vet run a culture on Mr. Jones for suspected Ringworm.

At Siamese rescue, the fosters are the ones that get the cats and kittens through their colds and illnesses. We try very hard to deliver healthy cats. But, sometimes it can't be controlled. Their adoption fee is $125.
Be assured that if a cat or especially a kitten has spent ANY time, whatsoever inside the shelter environment, it has contracted the cold virus, not to mention the corona virii. The cold must run it's course, but antibiotics, as Kim said, are helpful in avoiding complications of secondary infection.

If the kitten has congestion in their chest and not just in the head, I would head for the vet. And if has persisted over one week, without seeing some resolution, I'd take him into vet too.

Try and think of it as the discounted adoption fee is helping to pay for a bit of the vet bills.