If I get around to building another trailer I would get it galvanised, I painted mine and used the best etch primer I could buy and then put hammertone over the top, funny thing though is the hammertone chips off the etch primer really easy but the few areas I didnt prime the hammertone hangs on much better, one of the areas not primed was the coupling so its gets plenty of knocks. I had read somewhere not to use etch primer under hammertone but didnt follow that advice, the etch primer hangs on really, really well and the hammertone is easy to touch up. Still reckon that gal would be best and agree with Trev that painting isnt as cheap as you first think by the time you add everything up.