First off, I only recommend that you do not trim your bird’s toenails yourself the first time, but instead have a competent pet store or avian vet show you how to do it. You can use http://aav.org/search/index.php to help you look up an avian vet in your area.
A bird’s toenails have a “quick” in them. If you cut the nails too short, you will cut the quick, causing pain and bleeding. Losing even a few drops of blood can be dangerous for a small bird like a budgie. If you have been shown how to properly clip your budgie’s toenails and are ready and confident enough to do it yourself, make sure you have some styptic powder on hand just in case you cut too far and nip the quick, which is easy to do even for experts. If you notice any blood, apply some styptic powder with your finger and hold with slight pressure on the tip of the toenail for a few minutes. Be sure to monitor the budgie for several hours afterward to make sure the bleeding does not recur.
Birds do not need their toenails clipped unless they are excessively long. Do NOT buy sandpaper perch covers, as these have been known to create ulcers on the bottom of birds feet. One great solution is cement perches, usually available at bird shops, pet stores, or online. These are easier on birds’ feet, and will keep their nails nicely trimmed with no need for clipping. They are a bit expensive, but worth it.
Buy a small parakeet size cement perch and place it over their favorite perching place, or at another high point in the cage. If he does not use it within a week, try moving it to a different location. It will take a while for them to get used to it, so don’t move it too soon.