Hello Tom,
Thank you for your question about where to send your soil samples.

The following link to the OSU Deschutes County Extension website provides soil testing resources. Information includes laboratories serving Oregon; how to collect samples; and how to interpret soil tests. You will need to contact the company directly to determine their individual-specific charge for this service. Once on the website scroll down to section entitled Soil Testing and Amendments:
Central Oregon Garden Publications | OSU Extension Service (oregonstate.edu)

If you need additional information, I recommend you call the Deschutes County OSU Extension office in Redmond at<personal data hidden>. Ask to speak with Amy Jo Detweiler (oregonstate.edu), a member of the Horticulture Staff. Amy Jo welcomes your home garden questions and is a great resource.