You can support PIVlab development by contributing code, writing documentation and giving a comment and rating on Matlabs FileExchange Website.
The best way for supporting PIVlab is to buy hardware (cameras, lasers, synchronizers) for PIVlab from OPTOLUTION, the company I am working for. If OPTOLUTION generates some money with PIVlab hardware, then I can spend more of my working time for improving PIVlab.
Have a look at the available hardware here, or contact us for customized hardware:
OPTOLUTION PIV hardware for PIVlab