cheaper Oanda automated trading API

Oanda's official automated trading API looks expensive for me.
I am seeking if there's cheaper way to trade on Oanda FXTrade with API.

My idea is to develop a software to pull current price from FxTrade GUI and trigger FxTrade to buy/sell. I know this is not very easy from technical perspective, but not a mission impossible.

My concern is if I disobey any law and Oanda policy if I do in such a way. From my understanding, it should be no problem since I don't crack Oanda software, but just create a tool to manipulate Oanda software.

Any comments?
thanks.

I think it is FxSpyder - Xaron posted something on this earlier - look at his posts.

Surprised there are so many old threads unanswerd regarding FxSpyder and its use with Oanda. Maybe no users stuck it out in their early days. What you mentioned above can be done via FxSpyder access to Oanda.