Q: how do i just order prints?  i see options for ordering cards, books, etc. on my computer but not just prints

What version of iPhoto are you using?  For iPhoto 9 click on the Share button at the bottom right of the iPhoto window and select Order Prints from the options presented:

Note:  I recommend that you crop the photos to the print size you want before ordering so that you can determine what part of the  photos gets cropped out rather than let the photofinisher's software do the cropping.

OT

what version of iPhoto? every one is different

In the current version you select the photos you want prints of and order prints under Share  ==> prints ==> order prints

LN