People used to drink about 3 bottles of white wine for every bottle of red, but that ratio is becoming more even. America has fallen in love with Merlot. You don't need to hire a caterer or rent equipment for every party, but you can get a quick and painless education about what is a fair price for food and services for events in your area by just looking at the menus. We're all different. We don't mind that you're shopping around, honestly.
Small budgets are normal for a lot of functions.
Guests will eat about 8 hors d'oeuvres per person, per hour of a cocktail party. Think about your stress level, and what you can reasonably hope to accomplish, when planning your menu. Then have extra for people who want seconds. Use your own common sense. I'm sure I'm going to get some feedback about that last observation, so let me just say that teenagers eat the most, the 14 to 22 year old set can put away any given amount of food in less than 5 minutes.