You can get an Onguard Bulldog Mini with cable for about $26 here: http://www.amazon.com/OnGuard-Bulldo...3659327&sr=8-2

I have that lock. I don't think a pair of bolt cutters would get through it, and if the thieves bring power tools with a portable generator then no lock, no matter how expensive, would be able to stand up to that.

I don't think you need a $70 U-Lock. A $20-$30 Ulock from a company like Kryptonite or Onguard is very good protection.