Hi! I'm looking for an IC to generate a clock signal for a DAC application (a personal project) that can be programmed to output arbitrary frequencies from roughly 1 Hz to 20 MHz. There is room for variation in the minimum frequency, but I need to get reasonably close to DC, and all of the affordable clock generator chips that I could find so far start at >1 kHz.
Further requirements:
- ideally no/few external components (although an input/reference clock signal is available, if needed)
- hand-solderable, bonus if DIP package
- programmable via SPI/I2C or similar
- reasonably low-cost (say < US$2)
- widely available in single quantities
Remarks:
- a single output channel is sufficient
- no constraints on output or supply voltage levels
Any suggestions? Admittedly, I could probably find one myself if I only searched for long enough, but if there's an obvious choice, I'd be happy to be enlightened.

Thanks!