casing for DIY circuits

what are good,low-cost,presentable DIY casing for most common DIY circuits? im having problem with the circuits i made, because it is not presentable just having a bare PCB with no covers. and hazardous as well since some of the PCBs deal with 220V 110V. are acrylic fiberglass good ideas?

The appropriate box has everything to do with how it's used. Common DIY boxes are acrylic, polycarbonate, steel, or thick cast aluminum. Metal's not such a bad idea because you can ground the box, so case shorts will blow fuses rather than electrify the case.