Is my wheel bearing going bad?

i think my 98 tahoe might have a bad wheel bearing. there is a sort of clicking noise coming from the front drivers side wheel that varies in speed in accordance to how fast im going. i just noticed it about 2 weeks ago and was wondering if someone could find this part for me online? ive looked for it but the prices vary from $6 to $120 and that just doesnt seem right. its a 1998 chevy tahoe LT with 4 wheel drive. also how long do i have to change it and what could happen if i dont?Is my wheel bearing going bad?Could be a bearing, but I would also check the U-joints at the wheel..as well as several other things...before you spend money on parts you don't need...get someone to check it..usaully they will do it for free..than get a second opinion..