It depends on shipping methods , countries and products. There are 2 shipping methods most Chinese sellers use:
1. Singapore Post/ HK Post: Usually called free shipping but slow ( Usually about 5 to 10 days to US, 7 to 15 days to Eur, 15 to 45 days to South America) . The tracking number is charged, so many merchants don't offer tracking number if your order is low value.(Our company : no tracking number for order under $20, unless you pay us $2.5). No taxes usually, as merchants can declare low price and it is easy to go through customs.
2. DHL/EMS : It charges fee and fast (3 to 5 days). Taxes depends on countries and products, not easy to go through customs (May be checked if you declare too low price). You can ask the provider to deal with the taxes.
My English is poor, hope this can help you.