You didnt read my answer neither, having a farm class 50 is a big handicap to up a level 20-30 (all mobs u need are grey ^^) no choice to farm level 40, sell them and buy 20-30 items... (thats why I up a new farm 35 to help my babies ^^)
Having a farm class its just the 1st advice we always give to all beginners, before and after patch, and no need to be 50, on alb 19 cabal matter enough to kill 10-15 yellows at the same time, without pause (infinite mana on cabal after 18) it will provide all money, equipment, and xp item u need...
(Don't know how time u need to up 18 or 19, before nerf siege it was 15 seconds, after maybe 1-2 hours, its a good investment !)
you are new so maybe you dont know few tips, like taking few towers (3 mini) with zerg to be 2L0 in 10mn and having ALL RA u need to xp fast (serenity...)
(and with farm class u drop 200 fires a day so no problem of mana or life :p)