You could get some from a charity shop and re-donate them afterwards. People will prefer china, as stated above.
Cafes nowadays serve teas in non-matching china. Once the food is served you don't really see the plates, so you don't even need to have a matching set.
The plates are probably the least bother to wash up, there will be pots, pans, cutlery and miscellaneous serving implements which create even more hassle.
Accept offers of help with the clearing up.
Ask everyone to bring their own plates, glasses and cutlery.
Just some ideas......