major speaker problems

Hey everyone im new here, but I just got my truck from my dad and have noticed that the left and right door speakers rattle horribly, especialy the right side. Ive pretty much figerd out that apparently their busted (or somtin) but it always rattles worse if i turn up the bass. I know i need to purchase new speakers, but i dont know what i should buy (im knew to this). I realy wanted to put in a whole system in my truck during the summer, and was hoping i could get some advice on what would be the best speakers or sets to buy and put in my truck. Be reminded im on a low budget and i prbly wont be spending over 300-350 dollars.

thanks for any help

EDIT: i figured it might be helpful if i included some information about my truck. i own a 99 GMC Sierra SLE, everything with the truck is perfect except for the speakers wich is driving me crazy.

i was just looking for new speakers for my truck yesterday and here is what i found that will fit in the stock mounting
http://www.pioneerelectronics.com/pna/product/detail/0,,2076_4083_32693,00.html

http://www.pioneerelectronics.com/pna/product/detail/0,,2076_4073_192089287_tab=B,00.html?compName=PNA_ ProductDetailComponent

you can get those speakers for half price on ebay
there should be no need for and amp as long as your head unit puts out around 50x4 watts but you shouldnt have to worry about it i think it will work and loud enough on the stock headunit

sweet those look nice

appreciate the help ill be probably buying these soon

thanks for the help!