Nothing to scoff about. Your budget allows for a wide variety of good speakers, both new and used. But first, there is no such thing as the "best" speaker at any given price point, new or used. There is only the "best" speaker for you and this will take a bit of time and exploration on your part.
Yes, the amp you are using will be important because speakers vary in sensitivity (efficiency). Also, some info about the size of room and furnishings will be helpful. How loud do you want to listen? Are yoyu looking to replicate concert levels? Do you like to sit at the front tabel of a smaller venue like a jazz club?Right now, all we know is your taste in music and that you want full range speakers. So I assume you won;t be using a sub-woofer.
Most important though, I suggets not aking for a recommendation by brand or model but rather by type of speaker. So I would first encourage you to listen to a variety of models if you have access to HI Fi stores near you. Bring your own music, pieces that you are very, very familar with and start listening for differences in the high frequency drivers in each model you audition. For example, horn tweeters sound very different than domes. And metal domes sound very different than soft textile domes. Which is best? They all are - that is up to you to decide which you have a preference for. We cannot tell you this. In my case, I prefer soft dome tweeters which is why all the speakers I currently own have this type. You need to find out what you prefer so that when someone recommends a Klipsch Reference or Paladium speaker (both have compressiion horns) and you already know you find this type of driver fatiguing, you can dismiss the recommendation. Or vise versa - you may love the sound of this type of driver. See what I am getting at?
Good luck and have fun in your journey to find the "best" speaker for you.