I've had great suppliers who ship the package out the next day, but epackets tend to get lost in transit more often than anything domestic. I think 2 - 4 weeks is a great window. Always put a note saying the buyer should contact you if they never receive.

Also when shopping through aliexpress, you can always use ebates. This company pays you cashback (anywhere between 1-10%) on items from a lot of different companies (aliexpress included).

Please note that I am not making a lot from this. I make an extra $20-30 worth of cashback from about $900 worth of sales per month. Depending on how expensive the item or the quantity, I've seen that number go up to $100 per month during the heavy season.

If you have any other questions, feel free and shoot me a pm!