Max, that is a great deal. It seems that in your case, so far, no gasoline has caused any gauge failures. I think I might just give these a try at that price.
The one's I purchased were approx. $100 ea and one failes shortly after connecting up. Myself and many others have consulted with several companies and all of them said theirs were not made to support gasoline. Diesel fuel at best.
I am anxious, but we finally concluded to just be religious to change the filters every 50 hours. However, I would like to have a tell tale sign on a gauge when there is a blockage of any type which could be other than just a filter, like the anti siphon fitting on the tank which I had fail on my previous boat.
I will do some more digging, but so far, this one looks good.
BTW, what motor do you have?