Sometimes you can find a deal on FB market place and elsewhere. Most of the time you won't. Especially if you have no experience with cycling and don't know what your needs are.

What type bike you get should be determined by how you want to ride it and for what purpose. Also the terrain conditions around you.

If you over paid for the current bike, you'll have to hope that someone else is willing to overpay for it again. Or just give it away or trash it for recycling scrap metal and consider that part of your education toward your cycling ability.

If you want to post a pic, try putting the pics on imgur.com or another hosting site and then just write the sharing URL link in the plain text of your message. Don't try to use any of the linking or image tools in the editor. Just type it out on the keyboard. Then remove the https:// and put a space on both sides of any . or dot that is in the link.

As a noob you also are limited to five posts in 24 hours or maybe it's per day.... so post wisely.