Best budget friendly solder and flux?

What would be the best budget friendly solder and flux for switch moding? I know that Kester and Amtech are the best but it's like $75 for both and Amtech isn't sold on Amazon so there's also shipping. is there any good cheaper option that is ideally sold on Amazon? I have everything else like a microscope, t12 stashon, and other tools. I've tried modding a switch before and believe the solder or Flux is the issue as it looked perfect but had boot and dat0 problems.