I'd disagree with Cathee's answer about using Alibaba.  Yes, you can get good products through Alibaba.  You can also get screwed.  There are many unscrupulous companies there.

In addition, many of the top companies don't even list their products on Alibaba, because they don't need to...they already have enough business, and dealing with countless inquiries from Alibaba, many of which will lead to nothing, is actually a waste of their time.

This is a bit of self-promotion, but my business does sourcing and procurement for you in China.  We have more than 20 years of experience, and relationships with literally thousands of factories across China.  We know who is reliable, and who is not.  In addition, because we represent hundreds of different clients, we have significantly more bargaining power, to get a lower price than you'd get if you just negotiate with them yourself.  And we provide QC services, to ensure that the product they send you is actually what you ordered.

We aren't the only business out there that offers such services (although I do think we're one of the best), but especially if you're fairly new to this, you'll benefit significantly from working through a company that has experience, and knows how to avoid the typical problems and mistakes of buying products from China.