If you think about it long term, braid will be the cheapest option. You can use it pretty much forever and when you want some fresh braid you can just flip it over. The initial investment is a bit more (power pro is about $20 for a 150 yd spool, i think) but you can usually get backlashes out without damaging the line, unlike mono and fc, and you can add a leader so you are not cuting off 6" of line every time you retie.