cl,
retired kitchen contractor going through the stuff i have accumulated over the years... i have 5-6 sections of soft copper 1/4" line for mostly under sink applications, like water filters, water dispensers, ice makers etc. most of these line already have compression fittings (ferrules, etc) already attached. you just have to screw them on... no need to be an expert..
Maybe you need one.... price depends on length, but start at $7