Programming for serial Scale

Question

I am going to develop a C# Windows Form application to pull a scale weight from a large Truck Scale. The problem is my access time to the scale is very limited. So I want to find a small desktop scale. Has anyone run into this issue and found a cheap scale to do testing on (maybe around $50)? I want to get the application at least to the point to be able to read from the small scale before I try it on the large production scale.