Go to your local Big 5 sporting goods and buy the Mossberg 500 Field/Security combo.
If you don't like the fit/action of the Mossberg 500, go for a Remington 870 and buy barrels suited for your purpose(s).
There's also other combos for those two models (i.e. deer/field, field/turkey, etc. etc.)
For an all purpose shotgun that's affordable, you're really looking at those two brands.
If you're looking at used, consider semiautomatics made by Remington or Mossberg, and occasionally berettas.