First, it dissapoint me because is verry weack , i cannot do nothing with it. I want a stronger one to can do some experiments and projects around it.Why does the laser you have disappoint you? Why do you want a stronger laser? What do you want to be able to do with it?
Cheap? How much are you willing to spend?
If you are good with soldering you can put together a dangerously powerful laser fairly easily for not much money. There is tons of information here about how to do it. Look around the forum and read. read, read.
You will need protective goggles for your eyes that are made for the wavelength of your laser. Even reflected laser light can cause permanent blind spots. Buy the glasses before you buy the laser.