Depends on what you want to do, how much, and how fast.
You can get a basic Lee Classic press kit for like $150-250 (can't remember exactly). You load one rd. at a time, and it's not very fast. If you shoot low volume, this is fine.
1. Deprime 100 rd.
2. clean cases if you choose.
3. Prime 100
4. Measure out powder for each case
5. Load, seat and crimp each rd.
If you want to do high volume (I do ) you can opt for a turret press, or even faster, a progressive press.
I plan on going with a Dillon Super1050 press, which is about $1500, plus all the other necessities that go along with it. So, I'll more than likely have $2,500+ in it when all is said in done. This is top of the line though, and you in no way NEED to spend anywhere close to that to start reloading.
I'm going this route because I plan on reloading a metric shit ton of ammo for myself. The more you load, the more you get to shoot.
Dillon's Super1050 in stock configuration is said to spit out 1,000-1,200rd/hr. There's a company that makes a bullet feeder for it which I'd like to add. So essentially, if I can figure out a way to put a pneumatic cylinder on the handle (shouldn't be too hard), it'd have a fully automatic reloading machine, probably capable of loading 1,800+rd/hr.
-Feed it cases
-Feed it bullets
-Feed it primer
-Feed it powder
-Turn it on
-Go have a sammich.
Take a look on Midwayusa.com in the reloading section to get an idea on prices.