First off I think it our choice of trainingweapon depends on whether you want to start practicing on your own, or join a club. If you are planning to join a club, I'd say wait and see what they are using. Some clubs prefer steel other nylon wasters. This might save you the costs of new/additional gear ;). Also, and this might be different from club to club, my trainer always has tons of extra gear with him you can use during training. That way you don't have to invest a ton of money into it in the beginning. For all you know it might turn out it isn't what you expected it to be after a few lessons:). You can use the HEMA alliance club finder to find a club near you http://hemaalliance.com/?page_id=686 .
That being said. I'd advice to start with a lighter weapon more specifically a wooden or nylon waster. The choice depends on what you are trying to do. For instance, binding is better practiced with wood since the nylon version is a bit floppy when it comes to this. The nylon version is great for doing flowdrills. It's about 1/2 or 1/3 of the weight of a normal longsword. It is a bit harder to get the feeling and 'flow'right, but since chances are you don't execute the motion the right way the first time it's better for your joints. The first time I did a flowdrill the wrong way using a steel longsword my wrists hurt for about a week ;).
Most of the schools I know (over here in the Netherlands) use a nylon waster as their first training weapon. We use the Rawlings nylon longsword (I'm kinda guessing you want to start practicing longsword). It costs around 70 euros (bit of a guess here) and the site where we buy them from is the knightshop. I bet there are US sites that sell them too.
These can be used for sparring too. However as Jim Barrows said about wood, since it isn't steel it reacts in a different way making you able to do things you wouldn't be able to do things with a steel sword. Also, even though it isn't steel nor sharp still use the proper protection. From what I heard from my trainer steel breaks a bone more or less straight, nylon tends to leave a mess (also you can still poke someones eye out ;)).
Now for the steel weapons you have two choices. A blunt steel sword, or a federsword.
I haven't used a feder yet but apparently it handles like a normal sword but is a bit safer. From what I know they used these at the Swordfish and HEFFAC tournaments, so I think they are the new tournament standard now (at least in Europe). The feders used at my club and at Swordfish are made by Peter Regenyei which is apparently on of the best in the business at the moment, or at least so I've been told.
Aah yeah, and please don't use the CAS hanwei ones. Those are banned from our club after breaking during fights and in particular after breaking during a stab resulting in the defender being pierced by it.
Another lesser know option (especially if you don't have a lot of room to practice) for flowdrills is the Swing http://www.mblades.com/ . I haven't used it yet, but apparently it is well received by the community.
I hope my reaction with what we use/ I've seen being used helps you out a bit with your choice.:)