From your question, I am not sure as to what you are looking for. If you are looking for a company that will pay you a salary to do some work for them at home (i.e. stuff envelopes) for a certain pay, then on that part you need to do your research on that company before you get involved with them.
If you are talking about a company product that you are trying to promote because you just spent, let's say, $97, on a product that someone else is promoting that is supposed to be able to generate hundreds - thousands in return, well that is a whole different story.
It is not the product/company that is not reliable. Sure there are some scammers on the internet and again that is upon the individual user to do their due process research. However the reason why there are so many individuals online that are finding it frustrating to make money online is because they skip the entire research factors when trying to promote.
These important steps are keyword research, traffic generation and list marketing. Many of these companies are making their money because they have teams of individuals who are doing all of the research for them and factoring in the emotions tied to their products that will actually sell their products.
The key is to build a list and do your own marketing and tweaking so that your sales material does not look like the thousands of others out there that may have already gotten the product months ahead of you and promoting the same way.
If you are looking for reputable companies and products, consider checking out clickbank.com and jvzoo.com
I hope that this helps you out.