I have bought many things on ebay. It is important to do your research ahead of time, to know if the prices you bid are reasonable. You need to know your personal limits. I usually buy specific things that I am searching for. The most expensive item we bought was an equipped van for my hubby's business. That was a $20,000 investment, so it was scary. But everything worked fine. We have had the van for over a year now, and it works great. My hubby is very pleased.
Most of the things we buy cost much less than that.
If you are new to ebay, I suggest you "watch" how some of the other bids are done before you try it yourself. Then, start small. Always check the feedback on the sellers. Carefully read all the notes (such as shipping costs, condition of item, etc.)
Feel free to email the seller if you have questions. If they don't respond quickly and politely with full information, then don't deal with them.