I think that the signal generator is closer to HP test equipment quality than Radio Shack quality, which may explain the price. I was expected a simple circuit, but when I looked inside it turned out to be very complex.
That's true though modern breadboards tend to be good to the low mhz range in my limited experience. Building breadboard computers in the 1-10Mhz range is well documented online.
Here's the brochure for the breadboard with specs and the price: https://archive.org/details/TNM_Elite_1_2_3_dynamic_breadboa...