I worked at a museum doing the exact same thing with oral histories. We used a Behringer USB interface, which was certainly not the best, archivally speaking, but was the best we could afford and in terms of the audio quality for access purposes worked fine.
We also used Audacity which, again, was not the best, but is a (free!) and intuitive program which in my experience was adequate for the purpose, and does have some sophisticated features if you feel like slogging through the lists of plugins.
Neither of these are perfect solutions or by any means the best in archival terms, but if your institution is really strapped for cash they can be an acceptable compromise between what you'd like and what you can actually afford to make the audio accessible!
Technical Services and Special Collections Coordinator
Allen Ginsberg Library
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