@Duran - This is a typical issue that most starter sellers face prior to learning. As Marc and everyone else might point out, your biggest burner could be investment in products that may not sell. Performing you basic research is 100% vital. Please also keep your emotions out of business. Just because we think something might (the keyword being might and not will) sell well, it does not necessarily sell well in the market. So research is vital. In research I would recommend classifying your research into Feasible Products, Feasible Prices.
It is important to find the right product at the right price to be able to make money online. So I cannot insist enough in you investing time and effort in research. Ok. I can see your face turning red. So Enough of advice :)
If you are looking to sell on Ebay, the easiest way to research is to use ebay itself. Tools like Terapeak ans Salehoo labs will do the trick too and given that you have a members in this community, you might as well leverage the salehoo labs. In ebay, you can perform basic research by searching for a product under any product category. It will throw out a couple of results and at this point, you should start focusing on the left side panel (the filter options) that ebay provides. Select New with Tags (NWT), New w/o tags, refurbished, others etc. Depending on your needs, play around with these filters to see what is currently being offered on ebay.
As next step, scroll down further on the left panel filters and select "sold listings only". This will give you list of products that have sold under the product category you are researching. It could be intimidating as the list of sold out products could run to pages. But remember, the long tail story. There is always a market big enough for a small player. With this, it should give you some basic idea on what products sell under the category and at what price.
The top of this search results page also holds some vital filters like Buy it now, Auction listing, All listing and then a sort function that would allow you to see results by highest priced, lowest priced, most recent (end date) etc.
One thing to keep in mind is that eBay is an extremely competitive marketplace. While ebay and amazon pretty much dominate this area of online market place, ebay is a little more relaxed than amazon when it comes to product photography requirements or listing guidelines though typically products tend to sell higher on amazon.
My recommendation is not to pay money for research. I did and burnt atleast a couple of hundred dollars trying to learn from the so called expert reports. I would not recommend going that route. Invest time into research and learning. Members in this forum would be more than happy to help share knowledge (atleast I would). So feel free to write to me or respond to queries in this forum and I will be happy to help you in anyway I can.