I just bought a cat carrier online for $40.90 (incuding postage). I went into a pet shop yesterday and they wanted $80 for a similar carrier to the one I had seen online. My rule-of-thumb is that I am willing to pay 20% extra to buy locally.
When I last took my cat, Spider, to the vet using my current carier he used brute force to break out of it. The new one looks much sturdier and has good reviews.