You could consider cutting out bad section of fuel line with small tube cutter and using compression fittings and piece of steel line between them. If rust is not too prevelant or advanced on rest of fuel line. Cheap and effective. Then just take a 3/4 inch brush and grease the rest of the line to retard future corrosion. Have found specialty type hoses pretty expensive myself but there are probably exceptions. I do not recomend any of this for brake lines. One other alternative is to go strip plastic fuel line from junk volkswagen diesel probably 85 or newer and work it in with short coupling hoses if needed. Possible same plastic fuel lines used on their gas models but my bentley manual is not clear on this and I do not recall one way or the other. I would do this if the whole line looked questionable. The vw fuel line is quite flexible and easily removed from junk car. Or it could just be used for the section of fuel line that is bad now as it should thread through old fastenings quite easily. Remember you asked for economical solutions. The only concern I have about the vw line is that I do not remember the diameter but suspect approx. metric equivelant of 5/16 inches. Oh yes retain the vw coupling hoses if you strip the line from one. A little scrounging and it's a free repair besides your time.