1, Transfect your cells with a vector containing GFP.
2, Put your plate or dish on top of  a DarkReader.
3, Take a picture of cells using a simple gel-documentation system from labsupplymall.com—you do not need an expensive fluorescence microscope to check transfection efficiency.

Example: Transfect Hela cells using GeneExpresso and PolyExpress in vitro DNA transfection reagent:

Of course you will see more clearly under fluorescence microscope:

Transfection in the presence of serum and antibiotics

Transfection in the absence of serum and antibiotics