To the OP, I was in the same boat as you when it came to editing video, I was using Pinnacle studio. I got a HD Go Pro, and studio just wouldn't handle the HD video. I was about to upgrade my Pinnacle to newer HD friendly version, but after some research decided against it. I guess Pinnacle is a huge resource hog of your computer's system, making it run REALLY slow.
I had it narrowed down to Magix Movie Edit Pro and Sony Vegas Movie Studio HD Platinum 10. You are able to download a 30 Day free trial of the Vegas from their website. There aren't any restrictions that I am aware of with the trail program, and you don't need to convert the AVCHD video, add codecs or anything like that. The program is a little intimidating at first as it has more options and detail than Pinnacle. Takes a little getting used to. I had to watch a few youtube videos to figure out how to do certain edits. Once my trail runs out, I will more than likely purchase it for good. I think it retails for $99.95, so it would fit in your budget that you stated.