If you want to trade as a retailer then you really want to use a distributor.
They will deal with the manufacturer / importing and you have a reasonable shipping time plus can use them to drop ship directly to customers
If you want a bulk batch then ideally speak to a UK retailer and you would get a bulk deal with reasonable shipping
Alibaba is an agent for wholesalers and depending on the item you could be looking at minimum order quantities of 100, 500, 1000 etc of a single item, Aliexpress is for smaller quantities and down to one item direct from the warehouse
Remember that the cheapest price listed is for the largest minimum order and to take into account import vat/duty & fees (which will be due for bulk orders), though if you’re regularly importing quantities as a business you can make arrangements to get them straight through)
You then wait a long time for delivery and have a lot of stock sitting, unless you have customers lined up and they are willing to wait