Considering getting ibook etc, etc for practice on

Hi, people, I'm back. Now that I already have an iMac G3 in my office and since I'm taking online classes to be a PC tech, I'd like to supplement my tech training (reason I bought the iMac G3 and Apple Support training book for OS X 10.4 (Tiger) plus the OS X Tiger Missing Manual book) by somehow getting an ibook or another mac laptop to practice taking it apart (please see these iFixit guides) Mac laptop take-apart guides

(if not to buy a newer Apple OS X support book later on, say, after I'm just about finished with my training on the iMac G3) so which model of mac laptop (I don't want any that are below OS X Tiger; however, this laptop can be newer) would you guys recommend I buy/look for either in the Thrift store back of our house, the Salvation Army store near the local mall, or accept from someone that my best friend has contact (she has contact with more people than I do ATM) with that's discarding the computer, and how much should I pay for it?

Lastly, I won't be ready to look for such a laptop to buy until probably this summer sometime, so just want ideas now.

Thanks in advance.

EDIT - this Mac/Apple training is to be a self-study program, taken on my own as a self-paced manner until I finish my current schooling at the community college (which will be in about 3 - 4 years from now) so that hopefully I'd have Apple experience behind my belt, and after which hopefully contact the Apple Training people about the intensive hands-on training at Apple HQ in Calif and the other Apple training HQ that's somewhere else (I forgot where) but I think there's at least 2 such training HQ's in the USA.

Well to reduce costs and get past OS X Leopard buying one machine that can get you upto or near the current OS would be more economical. If you want to dismantle a laptop and work with a newer OS I would suggest getting a 2006 polycarbonite MacBook. The Power PC based Macs can only get up to OS X Leopard, and that can be with a little hassle I have heard. A first gen MacBook can be found for somewhere around $300 if not cheaper depending on the specs. That will get you up to OS X Snow Leopard with the CoreDuo intel processor. Also they are not impossible to dismantle. If you can afford the $300 I say go for it,if not an iBook may be able to get on Leopard and you'll still learn from it.

I would recommend a powerbook if you are going to go for a PPC machine of the 2005 iBook g4. If you are going for intel then you should get really any of them except for a first generation macbook air.