Woot offers Decathlon ST100 Mountain Bike for $269.99 (orig. $398.99). Free shipping for Prime Members.

Product Description:
A LIGHTWEIGHT, COMFORTABLE, FUN FRAME
  It isn't always easy to get the right position on a mountain bike. Our designers created a frame that's easy to get onto.
  The 100% aluminium CGF frame (Comfort Geometry Frame) is both comfortable and easy to handle. The slope angle has been designed to keep your back straight, while the rear bases were shortened to make the bike very agile in turns.
 
Front suspension
  The 80 mm front suspension helps you get started with overcoming obstacles on slightly uneven trails easily.
  Its mechanical spring is a stamp of reliability. And the fork is particularly easy to maintain.
  To adjust the stiffness? It's very easy using a single dial.
 
DERAILLEUR & DRIVETRAIN:
  3 x 7 speed chainrings, 21 speeds total!
  2 easy-to-use grip shifters on the handlebar.
  Left (chainrings): control ascents/descents.
  Right (speeds): more precise control over your pedalling.
  In detail:
  Triple-chainring chainset (22/32/42 teeth) + protection / grease.
  MICROSHIFT FD-M20 FRONT derailleur
  MICROSHIFT RD-M25 REAR derailleur
  MICROSHIFT MS25 grip shifters with speed indicators
  SHIMANO TZ500 7 cog cassette, 14 to 28 teeth
  Large, solid KMC Z51 chain
 
HANDLEBARS, STEM, GRIPS
  With a stem that tilts 10° upwards, the riding position of the ST 100 is raised, accessible, and comfortable.
  In detail:
  Aluminium stem, 90mm long, with a 10° angle for maximum comfort.
  620mm wide steel handlebar, for stability and control.
  Grips in "soft touch" material' for good grip and a soft comfortable feel.
 
Saddle
  The saddle of the ST 100 is welded to prevent any movement of the saddle. And because your comfort is our priority after your safety, we've added an exclusive wider Ergofit saddle with a hammock shape.
  Easily adjust the height of your saddle with the Flex steel seat post (350mm or 400mm long depending on the bike size). Its smaller 27.2mm diameter provides your seat with natural flexibility, 30% more than a standard solution.
 
V-BRAKES WITH PADS
  Two V-Brake pads for effective braking.
  These brakes are composed of callipers that exert more or less pressure on the rim to slow or stop the rotation of the wheels.
  Thanks to the special design of the ST 100's aluminium brake levers, you only need two fingers to brake.
27.5" WHEELS & TIRES FOR DRY TERRAIN
  The wheels of the ST 100 are tolerant and robust, with 27.5" double-walled 28-spoke rims (26" for the XS size). Start overcoming obstacles fearlessly, including small rocks, cracks, holes and bumps!