looking for dyes that won't stain cells

[tigerrat]

Hi all,
I'm looking for a recommendation: I need a cheap fluorescent dye that won't stain any part of my NIH-3T3 cells(a little endocytosis is OK) but is also soluble in water.
So basically, rhodamine/fluorescein won't work because they do tend to get through the membrane of unhealthy cells.

Some of the alexa dyes or Fluorescein-dextran on the other hand would work but they cost too much for the experiments I'm doing .

Thanks a lot.