Depending on what kind of computations you are doing with MATLAB (and on which toolboxes you are using), Python could be a good alternative to MATLAB.
For the data, you can, for example, save your data directly in text file (assuming that you are not directly concerned by floating-point precision issues) and read it in Python.
If your data are Excel data, where each value is separated by a ";", you can for example read the file line by line, and use the split() method (with ";" as argument) to get each value.
For MATLAB up to version 7.1, it is possible to directly load .mat files from Python with the scipy.io.matlab.mio module.
Pandas is a Python data analysis library that can import/export from Excel pretty easily. Here's how to do it:
import pandas as pd data = pd.read_excel('foo.xlsx', 'Sheet1', index_col=None, na_values=['NA'])