Check out the "looking for a trainer, what's available" sticky at the top of this forum. It will be hard to find a warbird trainer for 100.00. Check out your area for up coming RC swap meets. you can run accross some great deals there. There is a lot to consider: In addition to the plane, you will also need, (for a glow Engine plane) an engine, fuel, glow driver, Chicken stick for starting, or electric starter, Prop, Receiver (Rx)for the plane, servo's, Transmitter (tx)-(radio) Rx Battery, fuel delivery system. all this is at a minimum. You can go electric instead of glow, but will still need the Rx and Tx, servos, motor, ecs, rx Battery. There are ready to fly models that come with verything you need, but not for 100.00. Hangar 9 sells a super nice P51 trainer that you can get ready to fly (RTF), but you're looking at over 300.00 for that. You can check out ebay as well or the Classified section here. There are deals to be had, but you just have to be patient and look for them. I've found a few good deals on Craigs list too. But the Swap meets that I mentioned earlier are where you find the best deals. Warbirds are difficult to fly. You might want to consider a standard trainer to "get yer wings" on. They are cheaper as well. Some guys will sell them dirt cheap as soon as they get their second plane. I still have mine and I think I'll keep it. It is easy and fun to fly, very relaxing. Other will tell you to find a club, join the AMA, and get with and instructor to teach you the facts about this hobby and how to fly as well, and they will be correct with those statements. A good instructor (and they cost nothing) is the best approach to learning this hobby and how to fly safely and properly. Last but not least, this forum is the best, an incredible source of information, friendship and advice.
Good luck and welcome to RC flying.