wont start, its gonna fight me the whole way

where could i get a multimeter for about 25 bucks i don't wanna dump a crap load into one cause i know i wont use it much? i found a guide on how to check the coil, but how do i know which field is + and - on the alt, i have the 3 wire alt(bat, fld, and fld) any sugestions? i think it may be the volts reg, had the problem before, how can i check that?