There are two DCP specs, the older DCI and the newer SMPTE spec. If you are talking about screening your film at one specific cinema then your best bet is to contact that cinema and find out which of these two specs their cinema supports. The SMPTE spec is probably the easiest to comply with for indie/amateur filmmakers as it supports video speed, whereas the DCI spec is more widely used but requires film speed only (24fps). BTW, both specs require a minimum 3.0 audio mix (not 2.0 stereo), although the de facto minimum for commercial DCPs is 5.1.
There is free DCP creation software available, so in theory you can create a DCP for just the cost of a hard disk but if you don't really know what you are doing then using an authoring house would probably be the wisest option.
G