I need to buy about 500 Styrofoam cups.

Sprawl Mart
Grocery store
Office supply store

Styrofoam is horrible for the environment. Maybe consider a different kind of cup such as paper.
That’s an especially odd request coming out of Eugene, Oregon. If anyone cares about the environment, it’s Eugene, Oregon!

If there is a CostCo nearby, find someone with a card. Otherwise your best bets are office supply stores. (And yes, Wal-Mart or Target.) It would be nice if you could try instead insulated paper cups. They feel a bit like thin Styrofoam but are infinitely better for the environment. Plus they are more compact in storage—they store more like paper or plastic cups than big, bulky Styrofoam.

Good call. I willl see if paper ones work.

cost is an issue…

Dixie Perfectouch™ Hot Cups 12 oz/500 ct $78.13 Item # 117087Top_Left_Nav-Top_search&lang=en-US&Nr=P_CatalogName:BC&Sp=S&N=5000043&whse=BC&ViewAll=35&Ntk=Text_Search&Dr=P_CatalogName:BC&Ne=4000000&D=cups&Ntt=cups&No=15&Ntx=mode+matchallpartial&Nty=1&topnav=&s=1

At Costco in Eugene, Oregon

Costco, any restaurant supply store. Washington has Cash N Carry (they may be in Oregon too).

Thank you Marrisa. I will be heading to the store in the morning. That is just about damn near perfect.