What i noticed when i built my bass was that time and money are inversely proportional to each other...
The more time you spend, the less it potentially costs and vice versa. The more you spend on tools, generally the quicker the project will move along.
I made the big mistake of sacrificing some quality to improve time and cost together.
What im trying to say i guess... is that you could use a lot of sandpaper, but to get good results it would take you a hell of a lot of time. Alternatively you can spend a little money on the right tools and the job will take less time.
Like these guys say.. find a bandsaw or scroll saw to save a lot of time, but if you have the time to spare, you can try a hand saw of some kind.
hope that helps... or at least makes some sense