Wireless data acquisition for PC
If your data collection system has a serial output, the least expensive way would be to wire straight across to the PC's serial port. Any terminal emulator program on the PC side could capture the data for you. If there is no serial output, you could bit-bang the data on an output pin. You'll need a level shifter in between to unless your hardware provides the 12v communication level the PC expects.

Easier but slightly more expensive is an HC-06 Bluetooth module such as this BT2S. It looks to your system like a serial port (connects to your system's serial I and O pins or your bit-bang pin(s)) and transceives via Bluetooth to/from your PC. Again, a general purpose terminal emulator program on the PC can collect the data.