I just got 99 herb the other day after i was tired of seeing it at 97. I was too lazy to sit there forever to level so i just did ovls till 99. With herb if you want to train it fast then just make the best pots you can. If you want to save money find the best gp/xp rate. I know recover specials are pretty good once you reach ( lvl 81 i believe? Can't remember ) you don't lose as much cash as you would think for not being able to sell them after.
You can actually make some faster cash and experience using Mousekeys. Check out this guide in the Runescape free guides section; http://sythe.org/showthread.php?t=1387721