That is a good question.  I am not aware of any classes being offered right now in Oregon but as they become more popular some of the counties might start offering classes.  Utah State University Extension Service has probably done the most research and has information on freeze dryers.  They have good information on their website.  The link below gives some good information on what you need to know before you purchase a machine.  
https://extension.usu.edu/preserve-the-harvest/research/buying-a-home-freeze-dryer-what-to-know-before-you-go

I agree with you, with the way food prices are sky rocketing, we need to look at ways to preserve our own foods, so we have a supply.  Each family needs to look at resources, storage facilities for the food and what foods are available whether you grow your own or purchase from local sources.  I am a strong believer in putting up food, so I have a supply all year and a well-stocked pantry, plus canned, dehydrated and frozen food on hand.  You might start looking on the Lane County Extension website for classes they will be offering this summer on food preservation.  Most are hands on, and the Master Food Preservers are very knowledgeable. I know a few own freeze Dryers and you could visit with them about their experience.  

Thanks for using Ask Extension

Nellie Oehler