clip-ons are less expensive and if they are the right colour look realistic.
about your hair condition:
righttt, i was in a similar situation - I had dyed my hair over 20 times and straightened my hair everyday for years, i had really long hair (under my boobs length) but i cut it into a bob to get rid of all the damage, I've also stopped straightening my hair and I'm sworn off dying my hair for at least a year because my hair dresser said it would fall out
honestly your best bet is to cut most of the damaged hair off, you can't repair damaged hair, full stop. that's why you get your split ends cut off. hope this kinda helps.