Pick a store that you feel would be a nice reliable environment to buy your collectable. This is because you cannot trust EVERYTHING you see.
Step2
You could always go the eBay route, although I do not recommend anything that looks suspicious. You should always look out for this when buying collectibles.
Step3
choosing a nice store is always a great route
The best thing that you could do is find a good store, possibly a chain store, that could be trusted and then all you do is look around in their stock for what you like the most