I have tried several different printing places and sizes: 4x6, 5x7, and 8x10.
If the images are straight out of a modern DSLR, then their aspect ratio is 2x3. This means that the 4x6 should be the whole image - no crop. However, this is contingent on the print service. Use a local professional lab or a lab that allows you to select your own crops online (like mpix.com).
Assuming a vertical photo, a 5x7 will crop a smidge off. Automated printing services will typically center the crop so that a bit is taken off both the top and bottom. If you use a service that allows you to select the crop, you could move the cropped portion to the bottom, top, or anywhere in between.
An 8x10 will need to crop the most off of the image in order to fit that aspect ratio.
If you want absolutely full size images like the ones you see on your computer screen (again, assuming these are 2x3 to start), then you need to print these sizes: 2x3, 4x6, 8x12, 12x18, 16x24...
Keep in mind that the more common sizes are 4x6, 5x7, 8x10, 11x14, 16x20...
So, if you plan on framing these images, make sure you have the frame first (unless you don't mind paying for custom frames). Another budget friendly option is to mat the photo within a standard sized frame (for example, print an 8x12 and mat it to fit into an 11x14 frame, which are ubiquitous and constantly on sale).