Most of these ideas are ways that invite others to help and pitch in for the cost of a meal. Entertaining is all about sharing, and so don't forget to ask others to help out, when appropriate.
1. Potluck: Forget cooking large amounts of food yourself and just have folks bring a dish. This will give you a bit of spare change to focus on other things like flowers or cloth napkins.
2. Ask guests to bring meat: One of the largest expenses you can incur during entertaining is your protein source. Grill out (try your local park if you don't have a patio or deck to do so) and have everyone bring their own meat. Serve sides that go with everything and everyone walks away happy and full.
3. Ask guests to bring alcohol: Although we've talked about inexpensive alcohol sources in the past, that doesn't mean even the cheap stuff doesn't add up fast. Friends who drink will usually be willing to bring something along to help cut costs.
4. Borrow from friends: Don't have service for 20 in your small apartment? Borrow from friends or neighbors for an easy fix. Do check to make sure what you're borrowing can be re-purchased in case something happens — borrowing is good, breaking heirloom china isn't.
5. Don't make a full meal: Try hosting a get together at off-peak entertaining hours. Instead of having folks for dinner, have them for S'mores and drinks instead. It's an easy way to buy less and spend more time with friends instead of being buried in the kitchen.
Do you have any tips or good ideas for throwing a more affordable dinner party?
Related: Casual Entertaining: BLTs for Dinner