This week Walgreens has Expo Markets (6ct) on sale for $5.99. But you can get them for $2.99 with the following deal:
Expo Washable Dry Erase Markers 6ct $5.99
Use $3/1 Expo Washable Dry Erase Markers Walgreens IVC
Pay $2.99 after coupon
It looks like Office Max has the 4ct for $2.50. So for extra 50 cents you get two more markers.