Comment by genxy
5 hours ago
tl;dr it uses
Texas Instruments ADS1299 (24-bit, 8-channel) analog-digital converter
There is no way to do what that chip does for less, maybe 7$ less but then not as good. They have priced it perfectly and I hate them for it.
https://www.digikey.com/en/products/detail/texas-instruments...
https://www.adafruit.com/search?q=24-bit%20adc
Part of what you're paying for with the ADS1299 is simultaneous sampling, which you can get by without. You could use a single-channel 24-bit ADC and multiplex it yourself with generic analog switch ICs. That gives you a much larger array of part-selection options.
Or try the newer ADS122S14.