Normally, people don’t sell ghast tears. CloudCentre sells Ghast tears though, for a price of 4 ghast tears for 1 grass
Yea people dont really buy ghast tears just because brewing isn't necessary (If you sell try 6:1). If you want to make some money people always buy shulkers or anything ore related (quartz, gold, diamonds, redstone etc).
People occasionally buy end crystals which can be formed with ghast tears, obsidian and glass however it is not really as profitable as selling other things as obsidian is not a cheap material unless you search nether fortresses, in which case you can make a decent amount of grass
