I was wondering if anyone had a good one that they used? I've tried a few calculation programs that all come up with different things, and a few tutorials which also give different directions.

The software/calculation of zi wei dou shu (purple star astrology) on the market is based on the different system or theory.
I think you are hard to believe it.
The main stars should be at the same places. They will not be chanaged by different calculation.
Some of the secondary(乙級) or third(丙級) stars will be at the different places because of different system.

My master used the main zi wei dou shu book, which wrote by Chen Xi Yi (陳希夷), to teach us, but the calculation of the Da Yun(大運) and ziao Yun (小運) are different on the market.

I think it is depended on what system you learn and follow your master.
Do not use Guru A calculation system and use Guru B to explain it.

Some one who has some freewares can share it to me also?

Sir Mullich, most of the softwares that calculates ZWDS are written in Chinese, If you want the english try delemme iziwai software