Talk to a reputable dealer about your needs. Watch loads of videos about the product. Most of us start with a zero knowledge base about chainsaws. Honestly, I had no clue on how to start one when my friend asked me if I saw one to pick it up. If I hadn't have watched a video or two I wouldn't have known that it needs a working pull cord in order to operate. The point is if you don't know what you are looking for a cheap price may not be that cheap. You might end up buying something that doesn't work.
Chainsaws can be dangerous. You need to make sure that you have a few safety items before you operate it. Wood chips fly, and if your grip slips do I need to explain anymore? Here is a list of items you'll need.
Ear Protection(Ear Plugs)
Eye Protection(Safety Goggles)
Hard Hat A well fitting helmet will do well.
Protective Apron Chaps Just in case that chain saw slips.
Gloves will help you get a better grip on the saw.
You do want to maintain that chainsaw. It's not really an expensive purchase, but it's not a cheap one either. Make sure that you have bar oil and 2 cycle engine oil on hand to keep it running well.