Alibaba is basically just wholesale aliexpress, most sellers have a minimum order quantity and have clear pricing scale depending on your order.

TCP/IP Illustrated, Vol. 1, it may be a little bit outdated, but the core concepts still stand.

Keep in mind that a lot of your local marketplace sellers just order rebadged stuff from alibaba. I’ve found literally the same electronics i’ve bought locally on aliexpress for like half the price.