Before this winter started I had a small rust bubble on the front passenger fender and now the whole flap of metal that folds under is so rusted that I could pull it off. What is the best solution? Wait till the winter is over and replace the whole fender?

 

Yeah or bondo and sand it

 

You could probably find a fender thats a decent color match pretty cheap. I got a door for 115.

 

depends how big it is and how bad it is....
if you think you can get the bubble cleaned up really good and put bondo on it then go for it....but if you cant and do a shitty job the rusts coming back.... thats proly the cheapest way...

if you got some extra money get a new fender?