I've bought some plants online. Of course what you recieve isn't exactly (or at all) what's pictured, and sometimes the government will confinscate the plant if they find out the package isn't really decoration. But that's all part of the game. Since you're not going for plants (or at the very least, fish with a 40$ air mail price tag), you can be pretty reassured that you will get exactly what you buy. Though if you go for test strips and they're discounted...they're probably expired. Check your water conditioner - if it smells complain to the company because it's probably gone bad. Amazon is a good place to look, ebay can be a hit or miss depending on who you're buying from. With online fish stores, you're already getting marked up for shipping. If it's just for supplies you could go to a big superstore like petsmart/petco who will have the discounted price but perhaps not the best quality or exact brand you're looking for.