Where in Jordan can I find cheap second-hand book stores that sell dictionaries and other language materials?

My friend is going to Jordan on a trip and he'll visit several cities. As a favor he owed me he promised to get me some books that I crave.

Can you guys tell me where are some places across the country where he could get me some books for a good price, preferable second-hand?

Edit: to be more specific, I am mostly interested in dictionaries, grammar books and other works pertaining to language in general, especially Arabic-to-other or other-to-Arabic (either MSA or Jordanian variety), published within the last century.

Obviously there are multiple bookstores in Jordan, but I don't know how my friend will plan his trip so I don't know ahead of time where to send him—instead we agreed that I'd provide him with some places and he'll try to fit them into his plan.

However, I don't speak Arabic plus I am not so sure how many second-hand vendors advertise themselves on Google Maps, hence my humble request to the community :)