I found the part #66847 Inducer motor ($200) for my 1992 Rheem Criterion RGDG... The ball bearings were going bad and HVAC companies want from $500 to $890 to replace it. Is it hard or anything tricky about replacing it yourself? I can order the part and try it myself or order the part and have an HVAC fix it if there are gas leakage issues or something? Thanks

They are usually fairly simple to replace, but bear in mind that the feedback you are getting here is from wiley, seasoned veterans of the trade. If you purchase one yourself, and end up hiring a pro to install it for you, at least you are saving yourself the substantial markup contractors usually apply to parts. In some cases, replacement parts come with replacement instructions. Contact the source and ask.