Aliexpress is great for a lot of things, especially cheaper electronics where the exact same item can be found at a much higher price locally. They also carry lots of branded items, but you have to be familiar with Chinese brands, some of them are top quality but unknown here. For food and supplements you would have to find a good seller and that's extra work to check feedback and reviews. Clothes and footwear, again, I would be hesitant, especially with sizes. If you are looking for computer parts like graphics cards and processors, many local computer shops do have some kind of web presence. If you are adventurous and want to try the items on Aliexpress, you can find some weird deals but it's risky. A friend bought a PC case with all the components and is very happy with it but I don't think I would take the risk myself. It pays to know the market and understand the risks and even be familiar with each of these sites. You can also check other similar markets like banggood and gearbest. In any case, I would avoid buying something expensive, as returning an item is practically not an option.