Simply go to PandaExpress.com and place your order to be picked up at your nearest location.
When placing the order, use the promo code "HONEY" to get $3 off an order of $5 or more. You pay online and don't have to pay when you pick up your food. (But still be sure to get the free sample they offer when you get in line! Gotta do research on what to get next time you order!)
At my local store, a "bowl" is $5.80 (so $2.80 after code) and comes with one side (such as fried rice or chow mein) and one entree. For an extra $1 you can move up to a "plate" (comes with a second entree). I can tell you from personal experience that a plate is a lot of food.
The code is good through 11/30/15, and I suspect it is a one-time use code (per account). I had success picking up an order for a friend who ordered separately from me.