I agree solo is a great unit for beginners & experienced vaporists. There is zero chance of combustion and almost no learning curve at all. You can get them for 160 from 2 different retailers that are here on FC and have excellent customer support and make any warranty issues a breeze to deal with or you can find one as low as 130 on ebay, but then you would have to contact arizer directly for support. There was some confusion about whether arizer would honor the warranty on ebay purchases but I think the final word was that they would honor it (you would need to verify that on your own as I haven't had to use my warranty and I don't think many others have either).
If you really can't swing the extra money I would say look at the flashvape (small learning curve and can combust but from the reviews, well with learning how to use it), the firewood, the vapolution 2, or possibly even the NO2. I dint have any experience with any of these units but all are well received, shouldn't combust at all (except the FV which can but it's worth learning from the reviews) and within your price range of $100. If you end up deciding on the vapolution though, you should check the thread because I believe the manufacturer offer to FC members is still valid abd you get a little extra for your $100 but check there formore info