Shops
The ps-garage shops are inventories of cars and items you can buy with the points you earned at the forums.

There are psg points and reputation points. You get psg points from posting at the forums, while rep points are from joining competitions.

Lower class cars require psg points points, while higher class cars require rep points. To buy an item, simply go into a store, go to the item you want, type in how many, and hit "buy".

For more info about the shop:
http://ps-garage.com/forum/viewtopic.php?t=396

Click the link below to go to the shop:
The Shop

Other than cars, you can buy tickets at the Ps-G store.

These tickets allow you access to special features at ps-garage, The Room (database of high-res modified car pictures useful for chopping), Custom User Titles, custom user bars, and more.

Please see these topics for more info:
The Room
User Titles
Username Change
Mini Userbar

Note: these items do not mean anything, they just show your reputation at the forums. Members buy them because they like the cars, or they like to show them off. Some even buy a car and parts, and do a chop according to what he/she bought.