Many online merchants offer free shipping. You may be required to make a minimum purchase, but those amounts are usually around $50. If you live near one the merchants, you can even choose site to store shipping which is normally free also.
Here is the simple math for online shopping. If you save 10% from an online special, $15 due to free shipping, $10 for not using your gas, that could be well over $30 in savings. Now if you shop only once a month online, you would save over $360 a year. Can you imagine what you would do with that extra cash?