In checking the website pricing from a few of the dealers who help sponsor this forum, it looks like the average price is around $549.95. So the price quote you got isn't out of line. If you are looking to get the lowest price, just make sure you are getting everything that some of the other dealers are offering. Things like the coil cover, maybe the environmental cover etc. And since this is your first detector, you might want to get a "package" that includes a decent set of headphones, digging tool, pouch to keep your goodies / trash etc. If you have a local dealer who can help answer some questions, that might be a plus. But if you are willing to buy the detector from someone who isn't local, shop around and get what you want, at a price you want.
The X-TERRA series is very versatile. It is an excellent "turn and go" detector, right out of the box. And once you become familiar with its functionality, you can tweak it to maximize its potential for the type of hunting you want to do. So as far as learning curve..........there is plenty of information availible to help you understand the detector. You can be finding coins within minutes of taking it out of the box. Finding those coins and pieces of jewelry that others have missed will take some "getting use to" and understanding the X-TERRA. If it were quick and easy, those coins and pieces of jewelry would have already been found. With that said, the X-505 is an excellent coin / jewelry detector. And it is the perfect detector for hunting parks, yards, schools etc. The flexibility of the X-505 can adapt it to just about any situation. I say "just about" because it is not designed for Prospecting (that would be the X-70 and 705). Nor is it to be used underwater. But for land hunting, it is an excellent choice.
I'd suggest you take a look at the eBook I've written for the X-TERRA series. You can find the link to it at the top of these posts. It should answer many of the questions you have about the functionality. Also, take a look at the FAQFAQ section near the top of this forum and do a search for posts concerning the 505. Don't hesitate to ask questions because there are a LOT of seasoned X-TERRA users on this forum. Most of all, take time to learn the functionality and practice in your own yard. There is much more to this hobby than simply digging coins and jewelry in parks and yards. The time you take to learn the proper recovery techniques, researching and finding places to hunt and the proper use of your X-TERRA and your time will be time well spent. JMHO HH Randy