Guitar Effects/Filters in real time using low cost DSP? I have an c5502 texas low cost DSP. 
I can capture sound trough its P2 input and process every separated sample after sending it to the P2 output.
Im trying to implement some kind of effect in the sound, but this DSP has very low memory so i cant storage the signal to process it as a whole after.

There is any way of implementing effects like overdrive or even low pass filters in real time? I have tried somethings and it seems they arent enough to change the sound by modifying only sample by sample (using past results and samples)...
I'm sure you can implement a simple fuzz or overdrive effect on that board. Apply asymmetrical clipping to you your data, and filter the result with a biquad IIR filter. You'll need a lowpass filter to smooth out some of the nasty high frequencies after clipping (try a cut-off frequency $f_c\in [4..7]$kHz), and you might want a parametric EQ to boost some mid frequencies. You can compute the filter coefficients using the Audio EQ Cookbook. You can probably do much more than that but this should get you started.