The cheapest options with much larger amount of logic are: Upduino v2.1 ($20) and the never dying EP2C5T144 board ($10).

The latter requires a USB blaster dongle to program things so the Upduino has the upper hand IMO, especially because it also has very lightweight open source tools.

The IceStick is also nice and a bit cheaper at ~$25 but it has a smaller 1k logic element Ice40 FPGA on it whereas the TinyFPGA-BX has a larger 8k logic element FPGA.