Case Study: Paris

Paris is famous for its city-sponsored bike-share program, Velib. Prices are $2.20 for a day-use pass and  $10 for a weekly pass that allows unlimited rides of 30 minutes or less. Additional half hours are $1.30. This is a completely different range of prices from standard bike rental, even by Copenhagen standards. Even if your ride each way every day takes an hour (or, say, 40 minutes, which is quite plausible) you're still looking at a mere $17.50 in overage charge and $10 base charge, or $27.50 for a week of bike commuting both ways. This is super cheap by any standard.

For those who are not familiar with bike-share, this is a terrific system for casual biking and tourism but it is not for everyone. In particular the bikes are typically heavy, they are not a standard hybrid bike with many gears, so they offer a lesser biking experience and are only comfortable for shorter rides. The system also requires that you drop off the bike at another bike share station -- if you are staying at a hotel and your work destination does not have a share station nearby, this makes bike share close to useless. So depends on your particular destination. Bike share is fundamentally a different product from standard daily or long-term bike rental, and it is terrific for casual sight-seeing and short commuter rides where share stations are close by. For longer rides or most commutes it is not very practical.

Two other important notes of a more practical bent. Velib is subsidized by advertising and a slight public subsidy-- it is more like a subway or bus or other public transportation than it is like car rental or standard daily bike rental. (The public subsidy issue here is complex and debatable -- short version bikes get broken and stole and the city has to pay to replace them). Also, with Velib the bikes are not guaranteed to be present, or working (a backwards seat indicates a broken bike) at every station. So your travel plans might be disturbed, especially on a nice day, when you don't find a bike present. Not a problem for casual sightseeing, otherwise its an issue. The NY Times story on this is illuminating: http://www.nytimes.com/2008/07/13/world/europe/13paris.html?pagewanted=all

The most prominent standard bike rental is fat tire bike rentals, at 25 euros per day 100 per week -- $32 per day and $130 per week. The bikes are not hybrids, but beach cruiser style bikes, these are not a great option for getting around by bike over longer distances, great and fun (although not my first choice) for cruising around and tourism.

Looks like other shops are renting more standard hybrid bikes with more gears and better (lighter) frames from 15 euros per day, or about $20. After lots of digging you can find an example online, maybe their SEO doesn't work for english? An example would be:
 http://www.parisvelosympa.com 
Which is charging 20 euros per day + 10 each extra day -- that's $26 plus $13 extra per day, putting a week at $104. They are renting city bikes and basic mountain bikes, that look much more comfortable and easy to ride than the Velib offers. None of these shops is offering an online reservation system, although it seems they have enough capacity to ensure rentals most times.