It's gonna be expensive. Unless you have a lot of free time, a line on some severely discounted parts, or a frame that is some awesome tubing and you want to build into your dream bike you're better off buying something off the shelf for $280-$350.
An unknown french frame with just the fork, headset and stem?
PASS
ETA:
Here's what you'd need, at a minimum, to be on your way to the coffeeshop.
- Handlebars
- Wheelset
- Cog
- Lockring
- Tires
- Tubes
- Rim Tape
- Seat post
- Saddle
- Crankset
- Bottom Bracket
- Chain
- Pedals
- Foot Retention
- Optional but recommended: Front Brake, Lever, Cable, Housing
I hope you have tools or a Co-Op nearby. Does it have French threading?