It’s a bit dated, but Corvair, the poor man’s Porsche. Fuck Ralph Nader, I loved the Corvair.
Inspector Lynley, the poor man’s Peter Wimsey.
Baby, the poor man’s steak.
Riker, the poor man’s Kirk.
Yes. Duplo is made by Lego. The proper comparison should be:
Mega Bloks, the poor man’s Lego.
Pacific Grove Muni, the poor man’s Pebble Beach.
motorcycle, the poor man’s airplane
Savannah, the poor man’s Charleston, the poor man’s New Orleans.
Monkfish, the poor man’s lobster.
…what?
White Albacore Tuna, the REALLY poor man’s monk fish
Ted Kennedy, the poor man’s John Kennedy.
Christian Slater, the poor man’s Jack Nicholson.
A classic: Chicago, the poor man’s New York City.
ELO, a very poor man’s Beatles
Whitesnake, a very poor man’s Led Zeppelin
or
Def Leopard, another very poor man’s Led Zeppelin
Eelpout, the poor man’s monkfish.
An LP with a skip, the poor man’s Philip Glass.
Toaster Struedel, the poor man’s Danish.
Danish, the poor man’s Swedish. (Just kidding, Danes!) 
For '80s/'90s action movies:
Charlie Sheen is the poor man’s Tom Cruise
Rob Lowe is the poor man’s Charlie Sheen
Jan-Michael Vincent is the poor man’s Rob Lowe
Dean Koontz, the poor man’s Stephen King.
Lee Jeans, the poor man’s Levis
or Wranglers, the poor man’s Levis
Nah. Mobile is the poor man’s New Orleans (complete with the poor man’s Mardis Gras).
Old Navy, the poor man’s Gap. Gap is the poor man’s Banana Republic.
For a while Asia Argento was the poor man’s Angelina Jolie.
A penny, the poor man’s nickel.