You didn't say where you are located. If you are in a hot but dry area, you can use cooling fans which are very inexpensive. These work on the principle of evaporating water and cooling the air.
If you are located in a moderately humid or humid area, you can use (1) ductless split systems (mfr. TRANE, MITSUBISHI, and a host of others) or (2) portable a/c units (MOVINCOOL, ADAPT, etc.). In the former case the condenser will be outside and only a small refrigerant piping will come inside into the small wall or ceiling mounted unit. In the latter case, you will need to make an opening in the wall to exhaust the hot air out.