Hi I'm planning on buying a arduino uno and I was wondering what I would need need to run it like cords and other items and also was wondering what simple projects I could do for under 10 dollars
They generally come with everything you need (a usb cable). Assuming you've already got access to a computer.
A relay shield is pretty useful and fairly cheap. It'll allow you to turn on or off domestic appliances (such as lights, kettles, heaters etc..). button and LEDs are incredibly cheep and make handy input/output devices for testing purposes.
The real fun though is ripping old redundant equipment apart and using the goodies that lay within. Motors, sensors and all sorts of useful bits can be reclaimed out of old redundant printers, scanners etc... Even the humble mouse has some nifty goodies that can be (ab)used for other projects.
With a bit of imagination you can rip apart an old floppy drive, reassemble it and wire up the motors to your arduino to build a crawling robot.
A solderless breadboard like [urlhttp://www.pololu.com/category/28/solderless-breadboards]these[/url] is very useful for temporarily connecting things. They come in many different sizes.
You can make cheap connecting wires by taking apart a short length of Cat 6 cable with solid conductors.
projects for under $10.00
precise control of a coffee pot.
hack the airwaves for your neighbors weather station
a solar powered light for the driveway that waits will later in the night and not turn on at dusk.
a motion activated night-light
a motion activated switch for the light on the stairs, or bathroom
a voltage display for your bench