I am about to lose my job. Who can look over the paperwork they have me sign during my exit interview and inform at to whether or not it is fair?

My job is being terminated as of March 31st as the place I am working is being sold. They have offered a retention bonus of 15% of my pay as opposed to offering severance pay if I make it through March 31, and this is after 21 years of service. I do not trust them and I know they have you sign numerous papers during the exit interview which I should have to go through within the next 6 weeks. I do not want to sign anything without first having an attorney go over the paperwork so as to be able to advise me whether or not the paperwork is fair and legal. I would also be concerned as to what the paperwork would do to limit my being able to receive and keep receiving my retirement pay from this company, as I have heard from previous employees that they signed confidentiality papers that would directly affect their retirement benefits if they did not keep quiet about what transpired when they were employees. Can I consult an attorney and what would it cost before signing anything?