I recently purchased a used GT Aggressor 1.0 2012 and while trying to raise the stem and handlebar I discovered that the steerer tube only came up about halfway through the stem. There are no spacers below the stem, and the stem bolt still screw in. I bought a new stem and handlebar this afternoon and the new stem still has the same problem with the steerer tube only coming up halfway through the stem. The bike has very few of the original parts, and the front fork is a Rock Shox Indy S.
So my question is this: What would be the cheapest way to lengthen the steerer tube? I've done a little research on my own and have come across several different opinions on the matter ranging from getting steerer tube extenders all the way to new forks. I use the bike for getting around campus and I'm trying to make this repair on a college budget. I don't plan on doing any hardcore mountain biking with it, but I wouldn't say that I only ride the bike on the street either. Any guidance or advice you all can offer is greatly appreciated!