Get a set of folding irons, a light, two point sling, and a 1-4 or 1-6 scope and you are good to go.
The scope part can't be emphasized enough. The scope has it all over irons or dots when targets are small (like a foot sticking out from behind a barrier @ 100 yds), the light is bad, or the target doesn't offer much contrast to the background. Even a shotgun scope like a 2-7x would be fine if you are on a budget.
