Yeah, and it requires a bit of timing to buy correctly.  The chart for ND[1] shows the variance of price in a season.  Buying when it is really cold is not a great idea.  Also, getting the larger tank allowed keeps you from having to do a refill in the middle of the winter.<p>1) <a href="https:&#x2F;&#x2F;www.eia.gov&#x2F;dnav&#x2F;pet&#x2F;hist&#x2F;LeafHandler.ashx?n=PET&amp;s=W_EPLLPA_PRS_SND_DPG&amp;f=W" rel="nofollow">https:&#x2F;&#x2F;www.eia.gov&#x2F;dnav&#x2F;pet&#x2F;hist&#x2F;LeafHandler.ashx?n=PET&amp;s=W...</a>