Cold weld is it any good?

I want to fix a few rusty ps and am thinking about using a cold weld. It costs about 4.50 cad. Has anyone used this stuff and is it any good? There is also a small gas welding system with two bottles one ithink is s gas and O2 much like the propane torch. Or I could get a small Arc welder for under 200$. Any Ideas as to which way I should go? I have only very rudimentry welding skills learned in high school about 100 years ago.