There's a price difference but nowhere near as drastic as what Snaaake is saying(unless its a regional thing)
Home Depot has plexi in say 24x30" for about 4-5$
I ordered online lexan in 12x24x1/8 for about 6$
plexi is fine to work with for straight lines- razor score it and snap, give it a little polish on the edge and it's good
lexan is a lot easier for using tools, saws, drills, etc it really does cut just like wood