Cheap substitue for true bar?
I'm new to board maintenance, but in most other sports I've always preferred to maintain my gear myself. I've read that base leveling is like the hardest thing to do, and I'm not sure if I would choose to tackle that myself or not... but at the very least I'd like to be able to inspect it myself (chances are it is fine right now). But the true bars I've found are all near $50. Any ideas for cheap substitutes, like a construction level maybe? Though I'm not sure one of those is guaranteed to be flat... just level.