CoolerMaster 212 Evo is king of the below $50 coolers but it is 160mm wide and won't fit into my case. So I need the best 155mm cooler under $50 that produces less then 50dbA sound. They all seem to suck below 155mm except when you get into the Noctua $70+ price range but that is too expensive.Thanks.
Find an old Hydro H50 or an H60. The H50 I have works great on my 1155 i5 2500k (29C idle, 55-60C under Prime loading), and hooks right on to the existing 120mm back exhaust fan. Definitely can find one for around your price and you'll never notice the dbA increase cause it's already on a 120mm fan.
I'll give you best answer for the effort, it actually is the best as well but I don't like going the water route. This isn't for my case, don't want my noob friend to cry to me that a leak killed his PC.