Rattle can ech primer

Im sanding the underside of my car and plan on applying a bedliner called Raptor. I want a primer on the surface first. Am i able to get a good rattle can eching primer? I dont have a very good compressor, so using a gun is really out of the question. Any experience with any good products?
I also have small pits in some of my metal in a few areas, that have not gone very deep, any advice on what to put on them or will they be ok if i get the surface rust out of the pits themselves and then just hit them with the eching primer? Thanks for any help.