I started with a $400 flat bar commuter (aluminum cyclocross frame) when I switched back to df's after having a recumbent for years.
Now I have 2 not-so-inexpensive drop bar (steel cyclocross frames) bikes: one for going fast and lookin' *hot* and one for utility/commuting/touring.
I loved my $400 Kona Dew, and my LBS gave me a great trade-in for her. Someone bought her, so she has a new home now.
What if you buy an inexpensive bike that is comfortable and fun to ride *now*, and plan to trade it in later? If your LBS does trade-ins, it can be a great experience.
My Kona gave me the chance to learn that I'm just not that comfortable on aluminum, and that flat bars are awesome for shorter rides but become painful on longer rides, and that I reeeeeeeally like low gears.
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson