Well, I only have 100 bucks total to spend for my new amp. I was looking at http://www.guitarcenter.com/Line-6-Spider-III-15-15W-1x8-Guitar-Combo-Amp-103944831-i1168996.gc You guys have any suggestions or tips in what to look for in a modeling amp?
You're going to need more to get a decent one. Definitely. Save up more, and go for a Fender etc. or a Marshall or you're lucky. Although that should be fine.
Depends on what kind of level you need it. If you are in a band that plays live shows you will need a good one. As Anand said, Marshall amps are usually the best for that. If you need it for personal use I think that one will suffice. If you are a beginner then you should go for something cheap and easy to use until you get a little better or start performing.