head lights

hi to all i just got a 1996 gmc and my low beams on my lights dont come on i have hi beam and the light on dash shows they are on but they arent i changed the light switch but that did not work a guy told me it might the dimmer switch but that is 300dollars and i am not sure that it any ideas

Please use punctuation and grammar next time, because I can't tell if your low beams are or are not working. The same goes for your High Beams. Do you have composite headlights or sealed beams? Are you sure that your MAXI fuse in your underhood fuse box isn't blown? I can't see all of your lights going out. Need to give more information next time.