I've never done aliexpress but I've done alibaba a couple of times.
One was to buy about 200lbs of snap-off razor knives. That went well but I got surprised a bit on the shipping charges. It was still the best deal we ever got on knives like that.
Another one was buying poly-woven nylon sacks for bagging corn. I got a great quote from one company for 10,000 of them but the deal fell through when they said I had to order 10k of _each kind_ required to fill a 20ft long shipping container before they'd send them. That would have been about 80,000 bags and I did not need that many. The next company took the job for only half a penny more per bag and zipped them right out after we made sure we were both clear on specs (holds 50lbs/23kg of corn) and when the run completed they informed me they were ready for pick up. In China. After a series of emails returned at 12 hour intervals with somebody that doesn't really speak English I get hooked up with another person in China that'll get them on a boat for me if I Western Union them the money which I ended up doing on my personal credit card because my business card (sanely) declined to Western Union money to somebody in China with an address that read roughly "Second street to the east of Bandowang & 127th St. third building second floor Mandowango Enterprises." But I got them on the boat. Then I had to scurry and hire a lawyer to file the proper paperwork before they landed so I'd be clear with Customs. So, yeah, if you think Western Unioning money to a random guy in China is bad I also had to hire a lawyer from New Jersey. Also the bags tear once you get 40lbs of corn in them.
