It's hard to price check a account if the seller isn't very trusted. People don't wanna buy a runescape account unless they know the seller isn't going to recover it. So you probably wouldn't be able to get to much for it on sythe. Might be worth your time to try and post it on playerauctions.
lvl 138 isnt worth too much but because of skills i would say about 100$ if you were trusted but because you arent i would say you could get mabye 50$ for it.
Reason beingeople dont buy accounts from little to no vouched people.By the looks of it your using an acc u made in 2008 and then went inactive and came back, so your join datemeans nothing, compared to if you were relitively active. Hope that helps, gettting 99 dung would add about 25-50$ extra if it has like 800k tokens and 99 dung, which should be fast for your lvl+ stats
Also quests add alot sometimes depending. Send me a pm with more info and id be more than willing to give you a more accurate price check, but 50-100$ is a rough quick price check for it.
I agree, people enjoy trolling way to much including myself on rs to be able to talk, and with lack of vouches, it will not be worth as much as you hoped.