Search this forum for fuel consumtion. I remember not too long ago somebody ran some numbers comparing nitro/elec.
I use a gallon of fuel in 2 weeks to a month when I'm running alot.
Replacement parts will bite your wallet too, depending upon your style and skill.
Some of the parts are consumables regardless of how you drive...glow plugs, bearings, tires, batteries, etc...
Not trying to scare you away...But there is more than just fuel to buy.
Unless you break some of the expensive parts(engine, chassis, radio....), most of the stuff can be replaced with a $20, and still have change left for a burger...