White Smoke from exhaust?

Hello. I have a 2003 Toyota Avalon with over 200000 miles.
I went to work at noon today and I did not notice anything
amiss. When I left work at 7 PM, though, a lot of white
smoke came from my exhaust when I started the car and it
did not go away immediately. I thought it had a slight oil
smell. I had no choice but to drive it home, which is ten
minutes away. As I drove, I could no longer see the smoke,
although it was pretty dark by then. I did not feel or hear
anything unusual as I drove and I made it back to my house
without overt issues. When I got home, I looked under the
hood with a flashlight and I saw nothing unusual and I
could not smell anything off. I did not check the oil since I
wanted to let the engine cool down from driving. There
were no warning lights on my dash. I will take it to the shop
tomorrow morning, but I am worried that there might be a
serious problem that I do not have the money to fix.