Looking for the best overall sourcer / wholesaler in Asia

I am hoping.to sell on Amazon soon and I am a bit confused about certain wholesalers in general in Asia. (I cannot find any inexpensive ones in other parts of the world). I am on a disability pension and unluckily cannot afford as much money as many others can.

Before I go on I have heard that in some cases individuals on these websites can scam you - take your money and not send product , send you an inferior Product or some other scam I feel I haven't got a lot of choice as money is tight. At the moment I can afford may be $ 400 worth of product and I would like to get 100 of them or thereabouts. At the moment I am looking at micro sd cards , flash drives , or possibly external hard drives. I may branch out into laptops or tablets if all goes well and I can make enough profit to be able to afford to do this.

There are three companies that I have found in my searches and I am hoping to get some feedback from all of you are there on which of the three may be the best overall as far as honesty , reliability and it in general over all trustworthiness.

The three company that I have found are :

DH GATE , GLOBAL SOURCE S , & ALIBABA

Thank you to anybody who replies to this post.