wifi repeaters or range extenders

[Terry Fox]

Has anybody messed with wifi repeaters or range extenders?

I'm going out of town to a place where there is a very marginal wifi signal 
inside a garden-style condo, from an adjacent building.  The wifi is open 
BTW (no wep, wpa, etc).  I was thinking of putting a wifi range extender 
just outside the condo, so the signal inside the condo is stronger.  Do 
those things work?  I don't plan to do any banking or ordering of stuff 
while using this open wifi, just a little surfing.
73, Terry, WB4JFI