The standard for those long audio shops is a tiny digital audio recorder such as my old Olympus WS-300M. The ones with the slide-out usb connection can be plugged right into your computer to transfer the recording. They run for hours and are small enough to easily conceal in a shirt pocket or, better yet, in a bra. And, refurbished ones can be had for a song, online.
Based in MD, near DC
Shopping from the Carolinas to New York
Have video cam; will travel
Poor customer service? Don't get mad; get video.