La Petite Moi... are you looking for a Classic or a New Vespa? What do you plan on using it for (i.e. distance travelled, small roads or highways)?
I own a vintage Vespa (1971 - 150cc Sprint Veloce) and while I love it it can be tempermental.
If you aren't completely stuck on the vintage scooters, go for the newer models.
The 50cc is has two stroke engine but is relatively cleaner running than the vintage bikes. These retail for about $4,200 Canadian.
The 150cc one has a four-stroke engine and runs much, much cleaner. If you were to get any of the new Vespas this is the one I would recommend. It gives you enough speed and isn't too big. This retails for 5,500 Canadian.
There is also the 200cc Gran Turismo... a very nice scooter with a lot of power. If you want a bigger scooter with a lot of power go with this... This one goes for 6,900 Canadian.
As for the vintage scooters, it really is a matter of taste and performance... Many like the 50cc bikes because they are small frame and don't go too fast. Personally, I never feel safe on these because they don't go that fast... I always feel like I am struggling to keep up with the traffic (the new Vespa 50cc have more power because they are tuned differently).
You can also get 100cc, 125cc, 150cc and 200cc Vespas. Once you have decided whether you want a small frame or a big frame and what size of engine you want it really comes down to the looks of the scooter...
The next hurdle is price... The scooter shop that I go to for service (
www.motoretta.ca) has Project Scooters (junk heaps in need of love), Ready to Ride (fine ridable scooters) and Fully Restored (gorgeously restored, usually hard to find models)
The ready to rides are often from the early 80s (they are easy to find in relatively good condition) and they range in price from 2,200 to 4,000 Canadian.
The Fully Restored usually range from 5,000 to 10,000 Canadian.
1959 - VBA - 150 (fully restored)
1964 - Vespa 90 (fully restored)
1984 - Vespa ET3 - (ready to ride)
1979 - Vespa P125 - (ready to ride)