So I am not sure if one would consider this "low end", but it was fairly inexpensive (around $275 for all) the pieces sure seem to work well together for me. I may want to get another microphone for the recorder (if you have suggestions, let me know). Here's what I just picked up.
Yi 4k action cam
Nice clear video, similar in size and functions (that I need) to the GoPro, only costing much less at around $99.
The iSteady Pro motorized gimbal
Really smooth, simple interface, and can even charge the above camera on the fly. Cost around $99.
The Tascam DR-05 digital audio recorder
Pretty easy to use, lightweight, and records for a long time from 2 AA batteries onto a micro SD card. Cost around $77. Great not just for vocalizations, but recording little spoken field notes such as temperature, humidity, other animals seen or not seen, terrain type, moon phase, what have you.
Looking forward to this spring / summer. These little expeditions are going to be fun! Hopefully I can get some more evidence.