I was entirely new to zappers a couple of weeks ago myself. After doing much research and talking to other people I finally went with the mini fg from Hulda Clark research. I nearly bought the terminator instead because it is less expensive. Read the Comeback Kids posts in the archives. He is very informed.
I finally settled on the minifg because of its versatility. It can be programmed with any frequency from 1 to 1,000,000. Thus far I am really impressed with it but would want to wait several months before giving complete feedback on it. I have talked to many who like the terminator as well. But I have parasites and fungal issues so I went with something that I could program individual frequencies into. Good luck on your decision making.
I ordered 3 mini fg's to get a discount and am selling the other two for 325.00 including shipping. If you are interestd let me know.