I know, lots of people like to make a bargain. But very often the bargain is just " you get what you payed ". Exact this expirienses you can get at Aliexpress. But this is not the hole truth.
Of cause you can make a bargain at Aliexpress you only need to know how and where. I'm shopping at Aliexpress since about 4 years and I really payed a lot of dues.
Aliexpress developed in a good way, so if you are a serious buyer the chances to get a full refund at Ali is quite good.
My advice is: read the product prescription very carefully.
Ask the seller all your questions about the product.
Sometimes the seller doesn't answer all questions, then you have to be stubborn, till you get all information.
If the seller beats around the bush, do not trust him
Only buy at seller which try hard to give you all details about the product.
Look at the sellers rating, there are trusted shops, mostly very safe.
Ask for real pictures.
It is up to you how safe your shopping will get.
Good luck
Peter