For $50, you should get some cheap tires and some Mr. Tuffy liners. Quality flat-resistant tires cost close to $50 each. You won't cry when cheap tires get chewed up by road debris.

I've used Kenda Kwests (which you can get in 1.75) and CST Selecta (which has a reflective sidewall stripe). I just got a set of Vittoria Adventure City tires for my dad's cruiser, they're very smooth rolling, good wet grip, also reflective. Not sure if those are wide enough for you, but they would work pretty well.