Radiator problem in car but not overheating?

I have a 2001 Honda Civic with 130,000 miles on it. Earlier this week I noticed it was smoking white smoke from where the radiator sits in the car. I put some coolant in it and I've noticed that the reservoir of coolant gets low within 1 day of me putting coolant in it. My heat works and my temperature gauge is normal so I know it's not overheating. Someone suggested a block in the radiator, something about getting it flushed out. I was told that expensive. I'm in college working part-time so I don't really have that much money.

Read more: Radiator problem in car but not overheating?