When it comes to cheap bindings I can only reccomend AGAINST one company. I bought a pair of agency bindings for my first board a few years ago. I broke the upper strap on my 4th trip up and bought a pair of ride SPI bindings, still use them 3 or more times a week during the season and don't see me needing any new bindings for a while. My second board has a pair of SP Metalizer bindings which I like but the straps are also a little weak on those, the ratchet chews them up pretty bad.
Get rides, even cheap ones. It will be worth your money.