Calculate the cost of 6 shirts at each store:

• Store 1: 6 \times \7.00 = $42.00$
• Store 2: 2 for \14.99$, so$3 \times $14.99 = $44.97$
• Store 3: 3 for \20.95$, so$2 \times $20.95 = $41.90$
• Store 4: 6 for \41.95$
• Store 5: Buy 2 get 1 free at \21.10$each, so$2 \times $21.10 = $42.20$for 3 shirts, and another$2 \times $21.10 = $42.20$for 3 more$= $42.20$total... actually 4 shirts purchased + 2 free$= $42.20 \times 2 = $42.20$

The cheapest option is Store 3 at \41.90$.