Look in the DIY forum here. Lots of info in there on how to make one. My setup cost about $35. You can even do it cheaper if you're willing to put more work into it.
If you follow the link on melevs' site for the float switches, the same company has whole "DIY" kits for like $35-$40. Gives you everything you need but the pump!
Is it float valves or float switches that have a tendancy to get stuck? Or perhaps it's nether one and I'm thinking of something different all together.....
Both can.I think it is really best to incorporate as much redundency as possible. One of each or at least two of the same. You can put a digital timer in the system for anadded safety factor. Digital because of the 1 second intervals your allowed to program
