IMHO, do it right and get the Classic Turret Press Kit here-
http://www.kempfgunshop.com/products.../KempfKit.html
Here is how to set it up--
http://www.surplusrifle.com/reviews2...ress/index.asp
Here is the way the Safety Prime system works.
http://tinyurl.com/lxapv
Kempf's kit comes with dies and everything else you need except a scale. You can get that from them too.
This is a wonderful press; will last for a long, long time and is tough, precision tool. If you want to add another cailber it is a small cost. For .357 Mag they will give you the Lee .38 Special dies with which you load both calibers.
You will not be sorry with a choice like this.
Finally, Federal Primers can be very touchy. Don't mean to disagree with my good friend rwilson above, but they are not recommended with Lee equipment. Some people load them anyway, but that can be dangerous as you can discover if you search this forum and others. Stay with Winchester and CCI and be careful when you reload.